Learn Python - Full Course for Beginners [Tutorial]

0:00 In this course, I'm going to teach you everything

0:02 you need to know to get started programming in Python.

0:04 Now, Python is one of the most popular programming languages out there.

0:09 And it's by far one of the most sought after for jobs.

0:12 And so if you're trying to get a job

0:14 or you're trying to, you know, automate your life,

0:16 or you're trying to write awesome scripts to do a bunch of different things,

0:20 then Python's for you.

0:21 Honestly, more and more developers every day

0:23 are moving their projects over to Python

0:25 because it's such a powerful and it's such an easy to use language.

0:29 A lot of programming languages out there just aren't very beginner friendly.

0:33 There's a lot of syntax.

0:34 There's a lot of like little things that if you get wrong,

0:37 the program will yell at you.

0:38 Python is the complete opposite of that.

0:40 You basically just type out what you want to do and Python does it.

0:44 It's that simple.

0:44 There's not a whole lot of syntax to learn.

0:47 The learning curve is literally zero.

0:49 You jump in, you can start writing your first program in seconds.

0:52 In this course, I'm going to teach you guys

0:55 everything you need to know to get started in Python.

0:57 I designed this course, especially for Python.

1:00 And each lesson has been specially designed with examples that will help

1:04 you along the way with so many people starting to learn Python.

1:07 The question isn't, why should you learn Python?

1:09 The question is, why shouldn't you?

1:10 And I think for a lot of people,

1:12 the reason they might not want to learn Python is because

1:15 they're intimidated or they're afraid that it's going to be too hard.

1:18 Trust me, I am going to hold your hand through this entire course.

1:21 We're going to talk about all the core concepts in Python.

1:23 We're going to look at everything you need

1:25 to know to start programming in Python and start being

1:28 confident and start writing scripts and start writing programs

1:31 that are awesome and doing cool things in your life.

1:34 Anyway, I'm super pumped to be teaching you guys Python.

1:36 I can't wait to get started in this course.

1:38 And I hope you guys stick around and follow

1:41 along with the course and learn this amazing programming language.

1:43 In this tutorial, I'm going to show you

1:48 guys how to install Python onto your computer.

1:52 And we're also going to install a text editor

1:55 that we can use to write our Python programs in.

1:58 So the first order of business is to actually install Python on your computer.

2:02 So what we want to do is head over to our web browser.

2:06 And you want to go over here to this page,

2:08 it's just www.python.org forward slash downloads.

2:11 And on this page, there's going to be two buttons down here.

2:17 And it's just going to say download Python 3.6.3.

2:20 And at least that's the version that I

2:22 have right now or download Python 2.7.1.4.

2:25 So here's the thing about Python,

2:28 there's actually two major versions of Python that are in use currently.

2:33 There's Python two, and there's Python three.

2:35 So you can see over here, this is like 2.7.1.4.

2:39 Basically, any Python two version we would just refer to as like Python two.

2:46 And here's like the latest Python three version.

2:48 And so there's these two versions that you can download.

2:51 And the first thing we have to decide is which version do we want to download.

2:55 And here's the basic difference, Python two is a legacy version of Python,

3:00 which basically means that it's like an old version,

3:03 and it's not being like actively maintained

3:06 or supported like officially by Python anymore.

3:09 Python three is like the future of Python.

3:11 It's like the newest version.

3:13 It's the one that's getting actively maintained and supported.

3:16 And so there's pros and cons to picking either one.

3:19 A lot of people will say like Python two has been around longer.

3:23 And so there's more like libraries,

3:26 there's basically just more Python code written in Python two.

3:30 So therefore, like there's a few more things that you can do in Python two,

3:33 then you can do in Python three.

3:35 But then again, Python two is not supported.

3:37 And you know, five or 10 years from now, probably no one's going to be using it.

3:42 Python three, like I said, is like the future of Python.

3:45 It's the newest version.

3:46 It's the one that, you know, is sort of being maintained going forward.

3:49 So for the purposes of this tutorial,

3:51 I'm going to be teaching you guys Python three.

3:54 So we're going to want to download Python three.

3:56 Now here's the thing, like, if you learn Python three,

3:59 or you learn Python two, the differences aren't very big.

4:03 There are a few differences in like some syntax and just some,

4:06 you know, little things here and there.

4:08 But if you learn Python three,

4:09 you'll be able to jump right in and code in Python two as well.

4:13 Don't let anyone, you know, tell you that you have to learn one or the other,

4:17 we're going to learn Python three just because it's

4:19 I think probably the best for a beginner to learn.

4:21 And so that's the one that we want to download.

4:23 So I'm just going to click download Python three.

4:25 And we're going to go ahead and download this version.

4:28 And when that's done downloading,

4:30 I'm just going to head down to my downloads folder.

4:33 And you'll see here, we just have this file, I'm just going to double click.

4:37 And we get this like Python installer.

4:39 So I'm just going to click through here.

4:41 And we'll be able to install Python three on our computer.

4:45 All right, when that's done installing,

4:46 we can just close out of this and we should be good to go.

4:49 So now we have Python three installed on our computer.

4:52 The next step is we need to choose a text editor.

4:56 So we're going to be writing a bunch of code.

4:59 So we're going to need some, you know,

5:01 environment or some program that we can write all that code in.

5:04 And really, you can write Python in any text editor,

5:07 you could write it in like notepad or text edit, it doesn't really matter.

5:11 But there are special text editors

5:13 that are designed just for writing Python code.

5:16 And these are called IDEs.

5:18 And that stands for integrated development environment.

5:21 It's basically just a special environment where we can,

5:24 you know, run and execute our Python code.

5:27 And it'll, you know, basically, like tell us how we're doing.

5:29 So if we're, you know, if we write something that's wrong, or we have errors,

5:33 it'll kind of point us in the right direction

5:35 of what we need to do to fix that stuff.

5:37 So in this course, we're going to be using an IDE.

5:39 And one of my favorites,

5:40 and one of the most popular IDEs for Python is called pie charm.

5:44 So I'm over here on this website,

5:46 it's called jetbrains.com forward slash pie charm.

5:49 And this is the IDE that we're going to be using in this course.

5:54 So I'm just going to come over here and click this big download now button.

5:58 And we'll go ahead and download this pie charm program.

6:01 Alright, so I'm getting this page over here.

6:03 You can see there's two versions of pie charm.

6:06 One is a professional version, and that one's like paid,

6:08 so you have to pay for it.

6:10 But then there's this community version down here,

6:12 and that's free and open source.

6:13 So I'm just going to download this one.

6:15 And this should have everything we need to get started using Python.

6:18 Alright, when that finishes downloading,

6:20 I'm just going to pull that up in my downloads folder.

6:23 And again, we can just sort of run this guy.

6:26 And I'm on a Mac.

6:27 So I'm going to have to drag it over to my applications folder.

6:30 Alright, so we now have pie charm.

6:32 And we have Python three installed on our computer.

6:36 So we're ready to start programming in Python.

6:39 And this tutorial, we're going to create our first Python program.

6:44 And we're going to be able to run it and see how everything works.

6:50 The first thing I want to do is open up pie charm.

6:53 So pie charm was the IDE,

6:55 the integrated development environment that we downloaded in the last tutorial.

6:59 So I'm just going to go ahead and search for it on my computer.

7:03 And I can just open it up.

7:04 And when we first open up pie charm,

7:06 we should basically just get a window prompting us to create a project.

7:10 So you can see that down here.

7:12 Actually, the first thing I want to do though is come over here to configure.

7:15 And I'm just going to click on preferences.

7:18 And I actually want to change the appearance.

7:22 So I'm going to go ahead and give this a theme.

7:25 So I just went over here to appearance and behavior, appearance.

7:28 And I'm going to change the theme to dark.

7:30 Just because I think it's a little bit easier to use and look at.

7:34 But you don't have to do that if you don't want to.

7:37 And so down here, I'm just going to click create new project.

7:40 And it's going to give us this little window right here.

7:43 So I can just name my project.

7:45 And I'm just going to name this draft.

7:47 And then there's this other option down here where it says interpreter.

7:52 Now, what we want to select is Python version three.

7:57 So if I click down here, you'll notice that there's a couple different options.

8:00 So I'm on a Mac computer.

8:02 And by default, Mac has Python version two installed on it.

8:07 If you're on a Windows machine, I'm not sure if it does.

8:11 But in this tutorial, we're going to be using Python three.

8:14 So you want to make sure that you have Python three selected as the interpreter.

8:18 Otherwise, you might not be able to fully

8:21 follow along with what we're doing in this video.

8:22 So now I'm just going to come down here and click create.

8:25 And this is going to go ahead and create our project for us.

8:29 All right, so now we have our Python project up and running.

8:32 And I want to show you guys how we can create our first Python program.

8:36 So over here in this draft folder,

8:38 and this is just that project that we created,

8:41 I'm just going to right click and I'm going to say new.

8:44 And I'm going to come down and click Python file.

8:47 So we want to create a new Python file, this will be our first Python program.

8:52 And I can just give this a name.

8:53 So why don't we just call this app?

8:55 And I'm just going to click okay.

8:56 All right, so now we have our first Python file open.

9:00 And we can just start typing in some Python.

9:03 So I want to show you guys just a very basic Python program.

9:06 And this is just going to be a hello world program.

9:08 So we're just going to print something out onto the screen.

9:11 So what I want to do is I want to type out PRINT print.

9:15 And I want to type in open and closed parentheses.

9:18 Now inside of this parentheses, we can make some quotation marks.

9:22 And inside of the quotation marks, I'm just going to type out hello world.

9:26 So this is like a very basic Python program.

9:29 And what this is going to do is it's

9:32 just going to print out hello world onto the screen.

9:34 And so now what I can do is I can actually

9:37 run this file and we're actually getting a little error here.

9:39 It wants us to create a new line at the end of the file.

9:42 And so now in order to run our Python program,

9:45 I'm just going to come up here to the top.

9:47 And I'm just going to click run.

9:49 And we'll click this run button right here.

9:51 And now we'll see what happens.

9:52 So it's asking me what I want to run.

9:55 I can just click app.

9:56 And down here at the bottom,

9:58 you'll notice that we have this text that just got printed out hello world.

10:02 And so whatever I print, or whatever I put inside of this print statement is

10:07 going to get printed out down below in the console.

10:09 So as long as you're getting that print statement to work,

10:12 then you've actually written your first Python program.

10:15 And as we go through forward in the course,

10:17 we're going to be writing all sorts of awesome Python programs.

10:19 And we're going to be doing all sorts of cool stuff.

10:26 In this tutorial, I want to talk to you about writing a basic Python program.

10:29 So we're going to write just a very simple Python program.

10:32 We're going to look at how we can go ahead and write our programs,

10:36 we're going to talk about how our programs are getting executed by Python.

10:40 And we're also going to draw out a little shape onto the screen.

10:43 So this is going to be pretty cool.

10:45 I'm excited to talk to you guys about just the bare basics of Python,

10:48 and really just sort of give you an introduction.

10:51 So over here, we have our basic text editor.

10:54 And so any of the Python code that I write inside

10:59 of this file is actually going to get executed by Python.

11:03 So this Python file has a bunch of Python code inside of it.

11:07 And basically what we're doing when we're programming in Python

11:10 is we're just giving the computer a set of instructions.

11:13 Right, that's really what programming is,

11:15 it's just like we're specifying a set of instructions.

11:17 And the computer is going to go off

11:20 and execute those instructions that we give it.

11:22 And so the more complex the instructions we give to the computer,

11:26 the more complex the tasks the computer can carry out.

11:29 So I want to show you guys how we can use some Python instructions

11:33 or some Python code in order to draw out a shape onto the screen.

11:37 So I'm actually going to draw out a little triangle.

11:40 So over here, we can actually print something out

11:43 onto the screen and Python using something called print statements.

11:46 So I can just type out print.

11:48 And inside of these parentheses,

11:50 I can just type some quotation marks and inside the quotation marks,

11:54 we can put whatever we want to print out onto the screen.

11:57 So I'm going to copy this and I'm actually

12:00 going to make a few of these little print statements.

12:02 And we're going to actually draw a shape.

12:04 So we're going to draw like a triangle type shape.

12:07 So down here, I'm just going to draw a forward slash.

12:10 And then up here, I'll make a space and we'll do another forward slash.

12:14 Here, we'll make two spaces, we'll do another forward slash.

12:17 And over here, we're going to make three spaces and a forward slash.

12:20 And now I'm going to draw like vertical bars going all the way down.

12:27 And actually, we can do some underscores here as well.

12:29 That'd be kind of cool.

12:30 All right, so now we have our triangle looking shape

12:33 and you can see it looks kind of like a right triangle.

12:36 So I can save my file.

12:39 And I can either come up here to run and click run app.

12:43 Or if you're using PyCharm,

12:44 you can also just come over here and click this play button.

12:47 And when I click the play button, I want you to notice what happens down here.

12:52 So down here, we have this little window and this is called the console.

12:56 And basically, the console is just a place

12:58 where Python is going to output some information.

13:01 So when we use this print statement, we're basically telling Python like,

13:05 Hey, can you print something out onto the console?

13:07 So there's a lot of situations where we're going

13:10 to want to see what's going on in our code.

13:12 And we can use that print statement and print things out to the console.

13:16 And we can basically like have a little window into what our program is doing.

13:20 In our case, we're just going to be printing out this triangle onto the console.

13:23 So I'm going to come over here and click this play button.

13:27 And you'll see down here, we're actually printing out that triangle.

13:30 So mission accomplished, we were able to print out our shape.

13:34 So I could really draw any shape I wanted as long

13:37 as I was able to specify it inside of these print statements.

13:41 So essentially, what Python's doing when I click that play button,

13:44 is it's going into this file and it's

13:47 looking at all of these instructions in order.

13:49 So the first thing it does is it goes to this instruction, and it says, okay,

13:53 they want me to draw out these like little

13:55 forward slash in this vertical bar onto the screen.

13:57 Once it does that, it goes down to this instruction,

14:00 it says, okay, they want me to print something out again.

14:02 When it prints that out, it goes down to this instruction, etc.

14:06 So Python is actually going to execute the lines of code that we write in order.

14:11 So the order in which I write the instructions matters a lot.

14:15 So for example, if I was to take this last line here,

14:19 and put it up here at the top.

14:21 Now when I save the file, instead of just drawing out that triangle,

14:25 it's going to draw out this little upside down bottom thing at the top,

14:30 and then the rest of the triangle down here.

14:32 So the order of the instructions actually matters a lot.

14:35 So this is basically how your Python programs are going to go.

14:38 As we go through this course,

14:40 we're going to learn more and more of these little lines.

14:43 So here, we're just using this little print function,

14:45 basically, it just prints something out onto the screen.

14:48 There's a bunch of little things like this that we can learn as we go through,

14:51 we'll learn more and more instructions that we can give to the computer.

14:54 But in this lesson, I just want to kind of show you guys the basics, right?

14:59 We can essentially just define these little instructions for the computer,

15:04 and the computer will execute them in order.

15:07 In this tutorial, I want to talk to you guys about using variables in Python.

15:14 Now in Python, you're going to be dealing with a lot of data.

15:18 So a lot of times in our program,

15:21 we're going to be working with all types of information and data and values.

15:25 And sometimes that data can be difficult to manage.

15:28 So in Python, we have this thing called a variable.

15:32 And it's basically just a container, where we can store certain data values.

15:36 And when we use a variable, when we put those data values inside containers,

15:41 it makes it a lot easier for us to work

15:44 with and manage all of the different data inside of our programs.

15:49 So variables are extremely helpful.

15:50 And it's sort of like a core topic in Python

15:53 that you're really going to want to know in master.

15:55 So in this tutorial, I'm going to teach you guys everything you

15:58 need to know to get started with variables,

16:00 we're going to look at what they are,

16:02 why they're useful, and we'll look at the different types of variables

16:05 and the different types of data that we can store inside of variables.

16:09 But over here in my Python file, I just have a very simple program.

16:13 And it's basically just printing some text out onto the screen.

16:16 And so this is actually a little story that I wrote.

16:19 It says there once was a man named George, he was 70 years old.

16:24 He really liked the name George, but didn't like being 70.

16:28 So this is a valid Python program.

16:30 I could go ahead and run this program.

16:33 And you'll see down here in the console,

16:35 everything prints out and it looks great.

16:37 So we have an awesome little Python program here.

16:40 But let's say that inside of our story, I wanted to change the character's name.

16:45 So instead of naming the character George,

16:47 let's say I wanted to name the character John.

16:49 Well, I'm going to have to go through and I'm going to have to manually change

16:54 the name George to the name John at every

16:57 place inside of this story where it's mentioned.

16:59 So I'm going to have to go over here and I'll say,

17:02 okay, John, I'm going to have to manually change that.

17:04 And then, okay, down here, we're gonna have to again,

17:07 manually type in John and change it to John.

17:09 So in order to change the character's name,

17:11 I had to manually go in and change it in both places.

17:15 And now let's say, okay, maybe we want to change the character's name age also.

17:20 So in addition to changing the name,

17:22 we also want to change the age, let's make them a little bit younger.

17:25 So why don't we say John is going to be 35.

17:28 And so you'll see here, I had to come here and manually change the age

17:33 and then come down here and manually change it again.

17:36 Right.

17:36 And now that we changed it, like it's going to work,

17:39 it's going to be updated in our program.

17:41 But you'll notice that in order to make that change,

17:44 like I had to look through the entire program,

17:46 find it where that value was and change it.

17:49 And this was only with four lines of the story.

17:53 Imagine if I had a story that was like, thousands of lines long.

17:56 And we mentioned the character's name and age, like hundreds of times.

18:00 I mean, I'd have to look through each one

18:02 of those lines and manually change the character's name.

18:05 And that is not a very good way for us to do this.

18:09 And it's really not a good way for us to manage the data in our program,

18:13 right, the character's name and the age.

18:15 And so we can actually use a variable in order

18:19 to store the character's name and the character's age.

18:21 And when we use that variable, it'll make it a lot easier for us to put

18:26 the character's name and age inside of our little program here.

18:29 So I'm going to show you guys how we

18:31 can create a variable for the character's name and age.

18:33 And I'm just going to go up here above this print statement.

18:36 And up here, I want to create a variable.

18:39 So when we create a variable in Python,

18:42 we actually need to give Python a couple pieces of information.

18:46 The first piece of information we need

18:49 to give Python is the name of the variable.

18:51 So I need to actually assign a name

18:54 to this container where we're going to be storing information.

18:56 And so all I have to do is just type

18:59 out the name of the variable that I want to create.

19:01 So I'm going to create a variable called character name.

19:04 So I'm just going to say character.

19:07 And I'm going to say underscore name.

19:10 And so generally, when you're creating a name for a variable in Python,

19:14 you want to separate different words with an underscore.

19:17 So I have two words here, and I'm separating them with an underscore.

19:22 And now what I need to do is I need to put a value inside of this variable.

19:27 So basically, what I can do is I can just say equals,

19:29 and over here, I can type a value.

19:31 So I'm just going to type out the character's name inside of quotation marks.

19:35 So we're just going to type out john.

19:38 So now we have a variable for the character's name.

19:41 And below this character name variable,

19:44 I want to create another variable called character age.

19:47 So we're just going to type out character underscore age.

19:51 And I'm going to set this equal to the character's age, which is 35.

19:58 So we now have two variables,

19:59 one representing the character's name and one representing the character's age.

20:03 So what I can do now is I can replace

20:06 the character's name inside of the story with this variable.

20:09 And I'm going to show you guys how to do that.

20:11 So if we want to put a variable inside of this print statement,

20:14 I'm actually going to have to do a couple of things.

20:17 The first thing I'm going to have to do is end off this text in here.

20:22 So I'm going to have to put a quotation marks here at the end.

20:26 And you can see I'm basically wrapping

20:28 this whole thing into a single like quoted line.

20:31 And now I also have this text over here at the end.

20:34 So I'm going to have to put a quotation mark here.

20:36 So now I have a bunch of text here in quotation marks.

20:40 And then I also have text over here in quotation marks.

20:43 Now inside of here, instead of saying the character's name,

20:47 I want to refer to that character name variable.

20:51 So I'm just going to say plus character underscore name.

20:57 And I want to say another plus sign.

20:59 So I basically am saying I want to print out all of this text,

21:03 plus the value that's stored inside of character name, plus all of this text.

21:09 And what this will do is actually print out the character's name.

21:12 We print this.

21:13 So I'm going to go ahead and run this program.

21:15 And you'll see down here, and actually let me put a space over here.

21:19 And we'll run it again.

21:21 So you can see down here,

21:23 we still are printing out there once was a man named John.

21:27 And so what Python is doing is when it executes this line of code,

21:31 it's coming over here and it's seeing, okay,

21:33 they want to print out the value inside of character name.

21:37 So it Python is going to go up here, it's going to get the value.

21:41 And it's going to insert it inside of there.

21:43 So I can basically do this for every instance of the character name in my file.

21:47 So I can, you know, I'll just copy this guy right here.

21:51 And I can just paste it down here where the character's name is.

21:55 So I'll paste this.

21:56 And you can see now we're doing exactly the same thing that we did up there.

22:01 I can also do this for the character's age.

22:03 So I'm going to come down here and I'll paste in what we just paste it in.

22:08 And I'm going to change this instead of character name,

22:10 we'll change it to character age.

22:12 And I'm going to do this in one more spot.

22:15 So we're going to do this over here where we're mentioning the age.

22:19 And again, I'll just change this to character age.

22:22 And so now when I run this program,

22:25 it's going to print out the same story that we were printing out before.

22:29 But now I don't actually have to type

22:32 in the character's name and the character's age.

22:34 I can just refer to this variable.

22:36 And the cool thing about variables is

22:38 if I wanted to change the character's name,

22:41 now all I have to do is change it up here.

22:44 So I could change the character's name to like Tom or something.

22:47 And we could also change their age.

22:49 So I could change the age to be like 50.

22:51 And now that's going to automatically update throughout our entire story.

22:55 So when I click this play button, you'll see now we're using the name Tom.

23:00 And he's 50 years old.

23:02 So that's where variables can come in handy.

23:05 And this can be a really awesome way to control

23:08 and manage the data that's inside of our programs.

23:11 With variables, you can also modify their values.

23:14 So for example, let's say that halfway through the story,

23:17 I wanted to change the character's name.

23:19 Well, I can just make some new lines over here.

23:22 And down here, I can actually assign a new value to one of these variables.

23:27 So I could say like character underscore name.

23:30 And in order to give it a different value,

23:33 all I have to do is just say equals, and we'll give it a different value.

23:37 So let's say halfway through the story,

23:39 we want to change the character's name to Mike.

23:41 Well, now when I run on my program,

23:44 you'll see here in the first part of the story,

23:46 it says there once was a man named Tom.

23:49 And in the second part of the story, it's referring to the name as Mike.

23:54 So I actually updated the variable inside of my program over here.

23:57 And that's a really awesome way.

23:59 You know, a lot of times in these programs,

24:02 you're going to want to be modifying the values of variables.

24:05 So you can do it just like that.

24:07 So finally, I want to talk to you guys about the different

24:10 types of data that we can store inside of these variables.

24:13 So over here, I have the character name and the character age.

24:18 And I'm actually storing what are called strings.

24:21 So a string is basically just plain text, right?

24:25 So the name Tom, that's just plain text.

24:28 Down here, these guys are strings as well.

24:31 So there's a data type in Python called a string,

24:35 and it's just basically going to store plain text.

24:39 So, you know, any text that you would have like in a story,

24:42 or you know, someone's name, you can store inside of a string.

24:45 There's also another type of data that we

24:48 can store inside of Python, which is numbers.

24:50 So in addition to storing text, we can also store numbers.

24:54 So if I wanted to store a number, for example,

24:56 let's say we want to store the character age instead of inside of a string,

25:00 we could store it inside of a number.

25:03 So I could just type out 50.

25:05 And when we're storing a number, we don't need these quotation marks,

25:09 you only need that quotation mark when you're storing a string.

25:13 So if I want to store a number, I can just write it out like this.

25:16 And in addition to using whole numbers, I could also use decimal numbers.

25:21 So I could say like 50.5678213.

25:24 And Python's going to be able to store that number as well.

25:27 So you can store all different types of numbers.

25:29 And we can also store what's called a Boolean value.

25:33 And a Boolean value is essentially a true or a false value.

25:38 And there's a lot of instances in programming where

25:41 we're going to want to represent true or false data.

25:44 For example, I could have a variable called like is mail.

25:48 And this would tell me whether or not someone was a male.

25:52 And in my case, it would be true because I'm a guy, right?

25:55 So I can actually this needs to be capital.

25:58 So I could sort of value of either true or false.

26:02 And actually, if we were naming this in Python, we want to use an underscore.

26:07 So I would say is underscore mail.

26:10 And this can be either true or false.

26:12 So true or false values is maybe not something

26:15 that you're used to dealing with like in the real world.

26:18 But in programming, we're going to be using true or false values all the time.

26:23 They're super important.

26:24 So like I said, there's three basic types

26:27 of data that we can work with in Python.

26:29 There's strings, which is just like plain text numbers,

26:32 which would be like either decimal numbers or whole numbers like this.

26:36 And there's true or false values.

26:38 And these are the basic types of data.

26:40 I mean, there's a bunch of other types of data that we can use.

26:44 But I would say 99% of the time as a new user and a new programmer to Python,

26:49 you're just going to be dealing with these three types of data.

26:52 So those are the basics of the data and also with variables.

26:56 And you're going to be using variables all the time in Python.

27:00 So you definitely want to practice up and get comfortable using them.

27:06 In this tutorial, I want to talk

27:08 to you guys about working with strings in Python.

27:11 Now one of the most common types of data that we're

27:14 going to be working with in Python is going to be strings.

27:17 And strings are basically just plain text.

27:19 So any text that we want to have inside of our program,

27:23 we can store inside of a string.

27:25 So I want to talk to you guys about all the cool things we can do with strings.

27:28 And we're basically just going to get

27:30 a full introduction into why strings are awesome.

27:33 So over here, I'm just going to actually print out a string.

27:36 So I'm just going to say print and inside of these parentheses,

27:40 I can type out a string.

27:42 In order to create a string, I need to use quotation marks.

27:46 So I can make an open and close quotation marks just like that.

27:50 Now inside of the quotation mark,

27:51 I can put whatever text I want the string to have.

27:54 So we could say like, draft Academy.

27:56 And so now we have a string with the text draft Academy inside of it.

28:01 So if I run my program, now down here,

28:04 we're going to print out draft Academy, as you can see.

28:07 And when we have these strings,

28:09 there's actually a bunch of cool things that we can do with them.

28:12 So one thing I could do would be to create a new line inside of the string.

28:16 So if I want it, I can come over here, and I could say backslash n.

28:20 And you can see it got highlighted in a different color.

28:23 And what this is going to do is it's

28:25 actually going to insert a new line into the string.

28:27 So now it's going to say draft on one line and Academy on another line.

28:31 So I'm going to click play.

28:33 And you'll see down here, we just get draft Academy.

28:37 In addition to the backslash n, I could also use a backslash quotation mark.

28:42 So if I wanted to put a quotation mark inside of my string,

28:46 I can't just put a quotation mark like that, because Python

28:49 is going to think that I'm trying to end this string.

28:53 So if I want to include a quotation mark,

28:55 I can just use this special backslash character.

28:57 And that's called the escape character.

28:59 And it basically just tells Python that whatever character comes after it,

29:04 we want to render literally.

29:06 So when I say backslash quotation mark, it basically means like,

29:10 Hey, Python, I want to print out a quotation mark.

29:12 And so now we'll be able to print out a quotation mark right there.

29:16 I can also use this to print out a backslash.

29:18 So if I needed to print out a backslash, I could say backslash.

29:22 And it'll just print out a normal backslash now.

29:25 So you can see just like that.

29:27 So if you want, you can use that backslash

29:29 to make new lines or print out quotation marks,

29:31 or you can just use it as a normal backslash.

29:34 In addition to just typing out a string here,

29:37 I could also create a string variable.

29:39 So I could come down here up here,

29:41 and we can create a variable and we'll just call it phrase.

29:45 And I'm going to set it equal to draft academy.

29:48 So I can store this string value inside of a variable called phrase.

29:52 And then when I want to print out that variable,

29:56 or I want to access that string variable,

29:58 I can just type the name of the variable.

30:02 And you'll see that it's going to print

30:04 out the value that was stored inside of it.

30:06 I can also use something called concatenation.

30:08 And concatenation is basically the process of taking

30:12 a string and appending another string onto it.

30:14 So I could come over here and I could say phrase, and I can say plus.

30:19 And now I can add in another string.

30:21 So I could say like, is cool.

30:23 And now this is going to say draft academy is cool.

30:27 So I'm basically appending another string onto another one,

30:31 they call that concatenation.

30:32 And so in addition to doing all that stuff,

30:36 we can also use special things called functions.

30:39 And a function is basically just a little block of code that we can run.

30:43 And it will perform a specific operation for us.

30:46 So we can use functions to modify our strings.

30:50 And we can also use functions to get information about our strings.

30:54 So I'm going to show you guys a couple

30:57 common functions we can use with these strings.

30:59 And they're actually going to do awesome stuff.

31:02 So in order to access one of these functions,

31:04 I can just say phrase, and then I can say dot.

31:06 And I'm going to show you guys a function that we

31:09 can use to convert this string entirely into lower case.

31:12 So I could just say phrase dot lower.

31:14 And I'm going to want to type an open and close parentheses.

31:17 And this will take this phrase,

31:19 it'll take my string and it'll convert it to lowercase.

31:22 So you can see now we just have draft academy down here,

31:25 but it's entirely in lowercase.

31:26 I could also do the same thing for uppercase.

31:29 So I could say phrase dot upper.

31:31 And this will convert the entire string into uppercase.

31:34 You can see now it's entirely uppercase.

31:37 So in addition to converting the string into uppercase and lowercase,

31:41 I could also check to see if

31:43 a string is entirely uppercase or entirely lowercase.

31:45 So for example, I could say phrase dot is upper.

31:48 And this is going to give me back a true or a false value.

31:53 So it's going to be true.

31:55 If the string is entirely uppercase, or false, if it's not.

31:58 And you can see here, we're getting a false value because this is an uppercase.

32:02 I can also use these functions in combination with each other.

32:07 So for example, I could say phrase dot upper, and then parentheses.

32:13 And then after this, I could say dot is upper.

32:17 And now what it's going to do is it's going to run this upper function,

32:21 it's going to convert it into uppercase.

32:22 And then it's going to run this is upper function right after that.

32:26 And you'll see now we're going to get a true value

32:30 back because it will have converted the whole thing into uppercase.

32:33 So you can see now we're getting a true value.

32:35 So you can use these functions one after another, it can be really useful.

32:39 And there's a few other ones that I want to show you.

32:42 So we can also figure out the length of this string.

32:45 So if I wanted to figure out how many characters were inside of this string,

32:50 I could just say LEN.

32:52 And I'm actually going to make an open parentheses.

32:54 And I'm going to make a closed parentheses.

32:57 So I'm essentially saying LEN.

32:58 And this is another function, it's the length function.

33:01 And inside of this LEN function, I'm actually passing this phrase variable,

33:06 I'm basically giving the length function

33:08 this, and it's going to spit out a number.

33:11 So it'll tell me how many characters are inside of this string.

33:14 And so you can see here we get

33:16 15 because there's 15 characters inside of draft academy.

33:19 So that's how we can get the length of a string.

33:22 And that's going to be really useful as we go forward and Python,

33:25 we can also get individual characters inside of a string.

33:28 So imagine if I wanted to just grab one of these characters,

33:32 like imagine if I wanted to figure out

33:35 what the first character in this string is,

33:37 we can actually use an open and closed square bracket, just like that.

33:41 And in here, I can specify the index of the character that I want to grab.

33:46 So if I wanted to grab the first character in this string, I can put in a zero.

33:51 So if I say phrase square bracket zero, this is going to give me that capital G.

33:56 And you can see down here, that's what gets printed out.

33:59 Now I want to point something out in Python,

34:02 when we're working with strings, a string gets indexed starting with zero.

34:08 So you'll notice that in order to access this G, I had to put a zero in here.

34:13 And that's because in Python,

34:15 when we use indexes on a string, we start with zero.

34:18 So if Python is counting the characters,

34:21 or it's indexing the characters in a string, it's going to start with zero.

34:24 So it's going to say G is zero, i is one, r is two, a is three.

34:29 So we would say that G is at position zero in the string,

34:33 i is at position one, r is at position two, a is at position three, etc.

34:38 So we start counting at zero.

34:40 So if I wanted to access the first character in the string,

34:45 this G, I have to say phrase zero, and that's just a special thing in Python,

34:51 and actually most programming languages do that.

34:54 So they'll start with zero.

34:55 So for example, if I wanted to access this a, I'm going to have to put zero 123.

35:01 So if I put three inside of here,

35:04 now we'll be able to access that first a, as you can see,

35:10 we get an a right here.

35:11 So this is actually really useful being able

35:13 to grab a specific character inside of a string,

35:16 and you're going to be using that a lot as we go forward in Python,

35:19 there's also another really awesome function that we

35:22 can use and it's called the index function.

35:24 And basically what the index function will do is it'll tell us

35:29 where a specific character or string is located inside of our string.

35:34 So I could say phrase dot index.

35:37 And I can actually give this a value.

35:39 So sometimes when we use these functions in Python,

35:42 we can actually give them information.

35:44 So I can give this a value.

35:46 And we would call this passing a parameter.

35:49 So I would call a value that I would give to a function a parameter,

35:53 and you'll hear that word a lot.

35:55 So for example, I could say inside of here capital G.

35:59 And now this is going to return the index of the capital G inside of our string.

36:05 So it should give us back a zero because G is at the zero of index.

36:10 And you'll see down here that we get a zero because that's where G is.

36:14 So for example, if I put an a inside of here,

36:17 like a lowercase a, it should give me 0123,

36:20 because that's where the first a is inside of this string.

36:24 So I can click the play button.

36:26 And you'll see it's giving us a three, you can also put actual words in here.

36:31 So for example, I could put like Academy in here,

36:33 or I could even just put like a C A D.

36:36 And this is going to tell me where this starts inside of my string.

36:41 So when I click play, it's going to give me an eight

36:46 because that's where Academy starts right 012345678.

36:50 If I put something in here that wasn't in the string, so for example,

36:54 if I put a Z in here, that's not in here, it's actually going to throw an error.

36:58 So when I play this, you'll see that we get this error

37:01 down here because Z is not found inside of our program.

37:04 So that index function, again, can be really useful.

37:06 And we'll be using that a lot.

37:08 There's also one more that I want to show you, which is called replace.

37:12 So we can say phrase dot replace.

37:14 And in here, I can actually give this to parameters.

37:17 So I can give this replace function to values that it can use.

37:22 And the first thing I want to you to give it is what I want to replace.

37:26 So for example, I could say draft.

37:28 And then I'm going to put a comma in here.

37:30 And I want to put in here what I want to replace draft with.

37:33 So I could just say like elephant.

37:35 And now instead of saying draft Academy,

37:38 this is going to print out elephant Academy.

37:40 So you can see down here, it just says elephant Academy.

37:43 So this replace function can be really awesome because we can replace

37:48 certain words or even certain letters inside of our strings with other ones.

37:52 So those are just some basic ways

37:54 that we can work with strings inside of Python.

37:57 And there's a lot of these different functions that we can use with strings.

38:01 These are some of the most common the ones that I just showed you right now.

38:05 But if you just do a Google search,

38:06 you can find all sorts of Python functions that you can

38:09 try out and use and you know, see what they do.

38:12 But you definitely want to get comfortable working with strings in Python,

38:15 because you're going to be working with them a lot.

38:19 In this tutorial, I want to talk to you about working with numbers in Python.

38:25 Numbers are one of the most common data types in Python.

38:30 And any Python program you write is most likely

38:33 going to be dealing with numbers at some point.

38:35 So I want to talk to you guys about just the basics of using numbers,

38:38 we're going to talk about the different types

38:40 of numbers that we can represent in Python.

38:42 And I also want to show you guys

38:44 some awesome functions that we can use with numbers.

38:47 So we can do certain like mathematical operations,

38:50 we can do some awesome things with numbers.

38:52 I'm going to show you guys all of that in this video, it's going to be awesome.

38:56 So first thing we can do is we can actually just like print out a number.

39:00 So if I want to write a number in Python, it's really easy.

39:03 I basically just write the number.

39:04 So I could say like print two.

39:06 And this is just going to print the number two out onto the screen.

39:10 So I can use a whole number like this.

39:12 I could also use a decimal number.

39:14 So I could say like 2.0987.

39:15 And Python is going to be just fine with that.

39:18 We'll be able to print that out under the screen as well.

39:22 I can also make numbers negative.

39:24 So I could make this 2.0987 a negative number.

39:28 And Python will be able to handle that just fine too.

39:32 And Python, we can also use basic arithmetic.

39:35 So I could do things like addition subtraction multiplication.

39:38 So I could say like three plus four.

39:41 And now this is going to print this out.

39:44 Or why don't we say like three plus 4.5.

39:46 And this will be able to print out the answer.

39:49 So we get 7.5.

39:50 And we can do addition, we can do subtraction,

39:53 we can do division, or we could do like multiplication as well.

39:56 So you can pretty much do whatever you want inside of Python.

39:59 And if you want to make more complex mathematical equations,

40:03 we can also use things to specify order of operations.

40:07 So I could use parentheses.

40:09 So for example, if I said three times four plus five,

40:13 what Python's going to do is it's going to multiply three and four together.

40:17 So it's going to be 12.

40:19 And then we'll add five to that.

40:22 So we should get 17.

40:23 But let's say that we wanted to change up the order, right?

40:26 I could actually put a parentheses around four and five.

40:29 And now it's going to add them first.

40:31 So it'll add four and five.

40:33 So we'll get nine, and we'll multiply that times three.

40:36 So we should end up with 27.

40:38 So you can see we can use those parentheses to specify order of operations.

40:42 So I could make like a very complex,

40:45 a little equation here just by using numbers and parentheses.

40:48 We can also use one other operation, which is called the modulus operator.

40:53 So I could say like 10, and use this percent sign, three.

40:57 And this is actually read 10 mod three.

41:00 And basically what this is going to do is it's

41:03 going to take the first number divided by the second number,

41:06 and it's going to spit out the remainder.

41:09 So it's basically going to say, okay, 10 divided by three,

41:12 that's going to be three with a remainder of one.

41:15 And so this is going to give us the remainder.

41:18 And you'll see down here, we get one,

41:20 because that's the remainder of 10 divided by three.

41:22 And that modulus operator can come in handy quite a bit.

41:26 We can also store these numbers inside of variables.

41:29 So we can store them inside of these variable containers.

41:33 So I could come over here,

41:35 and I could create a variable called like my underscore num.

41:39 And we'll just store a value of let's say like five in here.

41:42 And so I could come down here, and I can just print out my underscore num.

41:46 And we'll be able to print that number out to the screen just fine.

41:50 So in addition to doing things like a basic arithmetic,

41:54 we can also do some other stuff.

41:56 So one thing I could do is I could actually convert this number into a string.

42:00 So if I wanted to convert this number into a string, I can just say str,

42:04 and I can put the number that I want to convert inside of these parentheses.

42:09 And so what's going to happen now is

42:11 this number is going to be converted into a string.

42:14 So when I click the run button, you'll see it's just printing out five,

42:18 but now instead of being a number, this is actually a string.

42:21 And this is going to come in handy

42:24 when you want to print out numbers alongside strings.

42:26 So I can come over here and I can say like, my favorite number,

42:32 and we'll be able to print this number along with this string.

42:37 So I can click play.

42:38 And it says five my favorite number.

42:41 If I was to get rid of this string right here,

42:44 and I wasn't converting the number into a string,

42:47 now Python is going to have a problem with this.

42:49 It's not going to allow us to do that.

42:51 You can see we get an error.

42:53 So anytime you want to print out a number next to a string,

42:56 you got to make sure that you use that little string function.

42:59 So there's a bunch of other stuff that we can do with numbers.

43:03 And a lot of times in Python,

43:04 you're going to want to be using specific, like more advanced math operators.

43:09 So there's a bunch of different math functions that we can use on our numbers.

43:14 And a function is basically just like

43:16 a little collection of code that does something.

43:19 So a function could perform an operation

43:21 like a mathematical operation on our number.

43:24 It could also give us information about our number.

43:27 So I'm going to show you guys some of the most

43:30 common functions that you'll be using in Python related to numbers.

43:32 The first one is called ABS, and it stands for absolute value.

43:37 So we can get the absolute value of a number.

43:40 And so over here, I'm just going to make this variable negative five.

43:46 And basically, I can just say ABS,

43:48 and I can make an open and closed parentheses over here.

43:51 And this is going to give me the absolute value of this number up here.

43:55 So when I click the play button, you'll see it's just giving us five,

44:00 because five is the absolute value of negative five.

44:03 I can use a few other functions.

44:05 There's another one which is called pow.

44:08 It's so it's just POW.

44:09 And I'm actually not going to use this variable.

44:12 We just use a normal number.

44:13 And this function is going to allow us to pass it two pieces of information.

44:17 So I can give this function two pieces of information.

44:20 The first is going to be like a number.

44:22 And the second is going to be the power that I want to take that number to.

44:27 So I could say like three comma two.

44:30 And this is basically just going to be three raised to the power of two.

44:34 So it's just going to be three squared.

44:36 So we should get nine down here.

44:38 You can see that we do.

44:40 So I could pass in like, you know, some crazy number,

44:42 like we could pass in a four and we could raise it to the power of six.

44:47 And so we should get like a pretty big number here.

44:50 And you can see we get 4096.

44:52 So this pow function is really useful for taking numbers to specific powers.

44:56 So in addition to using this pow function,

44:59 we can also use another function which is called max.

45:02 So I can say max.

45:04 And what this is going to do is it's basically going

45:07 to return the larger of the two numbers that we pass into it.

45:10 So right now I'm giving this a four and a six.

45:14 And this should tell us which number is higher.

45:16 So over here, it's just printing out six because that's the bigger number.

45:20 I can also use another function called min.

45:22 And this is going to do the opposite.

45:24 So now instead of printing out the max number,

45:26 it's going to print out the smallest number.

45:28 And it's going to print out four down here,

45:30 as you can see, another cool function is called the round function.

45:34 And this is going to allow us to round a number.

45:37 So it's just going to follow like standard rounding rules.

45:40 So if I said like 3.2 inside of here,

45:43 now it's going to round it down to just normal three.

45:46 But if I said like 3.7, it's going to round it up to four.

45:51 So that'll allow you to round a number.

45:53 So there's a few other functions that I want to show you guys,

45:57 but in order to get access to them,

45:59 I'm actually going to have to do something called importing.

46:03 And in Python, we can actually import external code into our files.

46:07 And so if I want to access these specific math functions,

46:12 I have to import something called Python math.

46:16 So I can just say from up here, math, import, and this star.

46:20 And basically, what this is going to do is it's going to go out

46:24 and it's going to grab a bunch of different math functions that we can use.

46:28 So I already showed you guys a few of these different math functions,

46:31 but there's actually a bunch more.

46:33 And in order to access them,

46:35 we're going to need to include this line of code inside of our file.

46:38 So once we have that, now I can access a few others.

46:41 So there's another function which is called the floor method.

46:44 And it's just FLOR.

46:45 And what this will do is it'll basically just grab the lowest number.

46:49 So it's essentially just going to chop off this decimal point.

46:53 And you can see over here, now we get a three,

46:56 because we're using that floor function, there's also another one called seal.

47:00 And that's just going to do the exact opposite.

47:02 So that's just going to round the number up no matter what.

47:05 So no matter what, we'll always get four

47:07 with we have a three point whatever here.

47:09 And there's another one which is called square root.

47:12 So it's just SQRT.

47:14 And essentially, this is just going to return the square root of a number.

47:19 So I could say like 36.

47:21 And now we should get six back.

47:23 So those are awesome, very interesting functions.

47:26 And inside of this math module, so we would call this a module.

47:31 And you don't have to worry too much about what that is right now.

47:34 Just know that when we put this line of code into our program,

47:38 it gives us access to a lot more math function.

47:41 So it basically allows us to do a lot

47:44 more things with math inside of our program.

47:46 And there's a bunch of different math functions in Python.

47:49 And if you want, you can basically just

47:51 go online and search for different math functions.

47:53 I showed you guys a few here.

47:55 And I would say the ones that we

47:57 looked at here are probably the most commonly used, but there's a bunch more.

48:02 And like I said, you know, there's tons of documentation on all this stuff.

48:05 So you can just look up, you know, math functions in Python.

48:08 And there's going to be tons and tons like lists of these things

48:12 that you can use inside of your programs to perform different math operations.

48:16 But for now, that's just been a little

48:18 bit about using numbers a little bit about doing,

48:20 you know, certain math operations and using functions with those numbers.

48:25 In this tutorial, I'm going to show you how to get input from a user.

48:32 So we're basically going to allow a user to input information into our program.

48:38 And I'm actually going to take the information that the user inputs,

48:42 I'm going to store it inside of a variable.

48:44 And then we're going to be able to do something with that variable.

48:48 So I want to show you guys how

48:50 we can actually go about getting input from someone.

48:52 And down here in my Python file,

48:55 all I have to do to get input from someone is I just have to type out input,

49:01 and then an open and closed parentheses.

49:03 And what this is basically going to do is it's going to tell Python like, hey,

49:07 we want to get input from a user and Python

49:10 will allow the user to type in some information.

49:13 And inside of these parentheses, we can actually type a prompt.

49:17 And so generally, when we want the user to enter in some information,

49:21 we want to tell them what we want them to enter.

49:24 And that's what we can put inside of here.

49:26 So I'm just going to say, enter your name.

49:30 So we're actually going to create a little Python app,

49:33 which is going to allow the user to enter in their name.

49:36 And then we'll store the name inside of a variable,

49:39 and then we'll basically just say hi to the user.

49:41 So we'll say like, hi, and then whatever the name they entered was.

49:45 So what I want to do is I actually want to store

49:48 whatever the user inputted into our program inside of a variable.

49:53 So I can actually go over here,

49:55 and I can create a variable, I could just call it name.

49:59 And I could set this variable equal to input.

50:02 So what I'm doing now is I'm taking the value that the user inputs,

50:07 and I'm storing it inside of this variable container called name.

50:12 And so now I have access to whatever they entered in.

50:17 So what we can do is we can say print.

50:20 And inside of the parentheses, I can just print out hello.

50:24 And then I'm just going to add on to this name.

50:28 And actually, why don't we put an exclamation point?

50:31 So essentially, we're getting a name from the user,

50:34 we're storing it inside of the name variable.

50:37 And I'm printing it out onto the screen.

50:39 So I'm going to go ahead and play this.

50:42 And when we run the program, you'll notice down here,

50:45 Python is giving us this little prompt.

50:47 So it's saying enter your name.

50:49 Now in here, I can actually type in a value.

50:52 So I can type in Mike.

50:54 And then I can just hit enter.

50:57 And Python's going to go ahead store this value inside of that variable.

51:01 And then it's going to print out hello, Mike.

51:03 And so this is kind of cool.

51:05 And actually, what we could do is we could prompt

51:08 the user to enter in more than one piece of information.

51:11 So I could actually copy this line of code.

51:14 And I'm going to paste it below here.

51:17 And why don't we have the user enter in another variable?

51:20 So we could have them enter in, for example, their age.

51:24 And over here, we just want to say enter your age.

51:27 And so now we're able to get two pieces of information from the user.

51:31 And I could say hello, name.

51:34 And then I can say, you are, and I'll print out their age.

51:38 So I'm just going to print age.

51:40 So now I'm basically able to get both

51:43 of these pieces of information from the user, I can get their name.

51:47 And I can get their age.

51:48 So when we run this program, I can type in both of those pieces of information.

51:54 So to say, answer your name.

51:56 So we could just make up a name like john,

51:58 and then enter the age, let's say john is 25.

52:01 And now it's going to say, Hello, john, you are 25.

52:04 So the program is able to get input from the user.

52:08 And then it's able to use that information in order to say

52:11 hi to the user and tell them how old they are.

52:15 And so getting input from the user is

52:17 a great way to make your programs more interactive.

52:20 And here, we're just scratching the surface, right?

52:22 We're just basically getting to, you know, a piece of information from the user,

52:26 but you can use these inputs to do awesome things in Python.

52:29 And as we go through this course,

52:31 you're going to see some really cool things that we can do with these inputs.

52:39 In this tutorial, I'm going to show you

52:42 how to build a very basic calculator in Python,

52:45 we're basically going to build a calculator

52:47 where we'll get two numbers from a user,

52:49 and then we'll add those numbers together

52:51 and print the answer out onto the screen.

52:53 So let's look at some practice in getting input from users.

52:56 And we'll also talk about getting numbers from users as opposed to just strings.

53:01 So I'm really excited to get started on this calculator.

53:05 The first thing we want to do is

53:07 create two variables and inside of those variables,

53:10 we want to store the two numbers that the user wants to add together.

53:14 So down here, I'm just going to say, num one.

53:18 And that's what we'll call our first variable is equal to.

53:21 And now I need to get input from the user.

53:24 So I'm going to say input.

53:26 And inside these parentheses, I'm going to say, enter a number.

53:30 And now I basically want to do the same exact thing, but for the second number.

53:38 So we'll paste this guy down here.

53:41 And I'm just going to say num two.

53:44 And then we'll just say, enter another number.

53:46 So now we're able to store the user's input inside of these two variables.

53:52 So now all I want to do is just print out the result.

53:56 So I'm actually going to create a variable called result.

53:59 So I'm just going to say result is equal to, and basically,

54:02 we just want to add these two numbers together.

54:04 So I'm going to say num one plus num two.

54:07 And now all we have to do is just print out the result.

54:12 So I'm just going to print result.

54:14 So we basically have our entire program written out here.

54:17 And this will allow us to enter in two numbers,

54:19 and then we'll add them together and print out the answer.

54:23 So I'm going to click play.

54:25 And down here, we can enter our number.

54:29 So I'm going to enter the first number, we'll say five.

54:31 And I'm going to enter my second number.

54:34 So let's say 8.0, or let's say 8.3.

54:37 So now we should print out the answer.

54:41 But if you look over here,

54:44 that's not quite the answer we were looking for, right,

54:49 five plus 8.3 is definitely not 58.3.

54:52 And here's what happened.

54:54 When we get input from a user by default,

54:58 Python is just going to convert it into a string.

55:02 So it doesn't matter what we put down there when we're entering the numbers,

55:06 Python's always just going to be like, okay, this is a string, that's it.

55:10 Sounds good, right?

55:11 It's just going to make it a string.

55:14 In order for us to make these num one and num two variables numbers,

55:18 we're actually going to have to convert the strings

55:21 that we get from the user into numbers.

55:23 And so the way that we can do that is by basically just coming over here.

55:28 And when we add the two numbers together, I can use a special Python function

55:33 in order to convert those strings into numbers.

55:37 And there's actually two Python functions that we could use for this.

55:41 The first is called int.

55:43 So I could say int, I can make

55:46 an open parentheses and I can make a closed parentheses.

55:49 And basically what this is going to do is it's going to convert

55:52 whatever is inside of these open and closed parentheses into an integer number.

55:56 And an integer number is basically a whole number.

56:00 So it's like one, two, three, four, five.

56:03 So it's a, it's a whole number.

56:04 In other words, it can't have a decimal point.

56:07 And so what I could do is I could say,

56:11 int, and I could put these inside of parentheses.

56:15 And now what this is going to do is

56:17 it's going to convert both of these numbers into integers.

56:20 In other words, into whole numbers that don't have decimals.

56:23 And it's going to add them together and we'll print out the results.

56:26 So why don't we do that?

56:28 And we'll just see if this works.

56:29 So I'm going to click the play button.

56:31 And down here, we'll enter our first number.

56:33 So I'm just going to enter in a four.

56:35 And then I'll enter in a five.

56:37 And now you can see it's printing out the correct answer four plus five.

56:42 And so that's essentially our basic calculator.

56:45 But we do have one problem with this calculator.

56:47 So I'm going to run it again.

56:48 And I'll show you guys with that problem is

56:51 if I wanted to add in a decimal number, so we'll add 4.3 and 5.5.

56:56 You'll see that we're getting this error.

57:00 And that's because I'm using this int function up here.

57:04 And this int function is looking for a whole number.

57:07 So if I put decimal numbers inside of there, it's going to break the program.

57:12 There's another function we can use instead of an int, we can say float.

57:16 And a float is basically just a number that has decimal.

57:20 So it's a decimal number.

57:21 So I can convert both of these guys into floats.

57:24 And now I'll be able to use decimal numbers.

57:27 So I can click play.

57:28 And I can just enter in some numbers.

57:30 So I could say like four.

57:32 And I could also say like 5.5.

57:34 And now it's going to be able to add both of those numbers,

57:38 even if one of them is a decimal.

57:40 And that's the beauty of using that little float function.

57:43 So in certain circumstances, you might want the user to only be able

57:46 to enter in an integer to a whole number.

57:49 But in a lot of cases, like in this calculator,

57:51 we want them to we want them to be able to enter any number that they want.

57:55 So we're going to use this float function.

57:57 So I'm just going to recap what we did one more time,

58:00 we created two variables, num one and num two.

58:03 And we basically stored the two numbers

58:05 that the users input into those variables.

58:07 And then we converted them into numbers.

58:10 And we added them together and we printed out the results.

58:14 So this is a pretty cool calculator.

58:16 I'm happy with it.

58:17 Hopefully you guys learned something.

58:18 And as we go forward in this Python course,

58:20 you're going to learn all sorts of ways

58:23 that we can make this calculator more complex.

58:26 In this tutorial, I want to show you guys how to build a madlibs game in Python.

58:34 So a madlibs game is basically just a game

58:37 where you can enter in a bunch of random words.

58:41 So like, you know, verbs, nouns, names, colors.

58:45 And you basically take all of those words and put them into a story randomly.

58:50 So over here, my web browser, I just have an example of a madlibs.

58:55 So, you know, down here, we're basically just taking random words,

58:57 like an adjective or a noun or a plural noun,

59:00 and entering them in side of a story.

59:02 So like you read through the story and then like

59:04 some random word pops up and madlibs can be pretty fun.

59:07 And I'm sure you guys have, you know, at least heard of madlibs before.

59:10 But if not, that was just a little introduction.

59:12 So I want to create a madlibs in Python.

59:14 And this is going to be really cool.

59:16 So down here, I have this like little poem,

59:19 which just says, roses are red, violets are blue, I love you.

59:22 And so, you know, this is kind of like a classic poem.

59:25 But I think we should mix it up a little bit and create a madlib for this poem.

59:31 And so instead of having this red color over here,

59:34 I want to have the user enter in their own color.

59:38 Instead of having violets, why don't we have them enter in a plural noun?

59:43 And instead of saying I love you,

59:45 why don't we have them say I love and then some celebrity?

59:50 So celebrity.

59:51 So this is the basic structure for our little madlib, right?

59:55 I want to basically have the user enter in a color,

59:59 enter in a plural noun, and enter in a celebrity.

1:00:02 And then I'll take all of those words and put them inside of our madlib.

1:00:06 And hopefully we end up with something that's pretty funny.

1:00:09 So how can we actually go about building this in Python?

1:00:12 Well, the first thing we're going to have to do is we're going

1:00:15 to have to be able to get these words from the user, right?

1:00:18 That's pretty obvious.

1:00:19 So I think what we should do is we

1:00:21 should create three variables called color plural noun and celebrity.

1:00:25 And we'll store the user's inputs inside of those variables.

1:00:29 So up here, let's create those variables.

1:00:32 The first variable I want to create is going to be called color.

1:00:36 So say color.

1:00:36 And I want to set this equal to the input.

1:00:39 So I'm going to say input.

1:00:40 And inside of here, I'm just going to give them a prompt.

1:00:43 So I'll say enter a color.

1:00:45 And we can basically just copy this line of code.

1:00:49 And I'm going to paste it down below.

1:00:51 And we'll paste one more time.

1:00:53 So now we're going to create our plural noun variable.

1:00:57 So I'll say PL, URL, plural noun.

1:01:01 And we'll just say enter a plural noun.

1:01:05 And actually, over here, I want to make a colon as well.

1:01:09 So then finally, we'll create our celebrity

1:01:12 variable and we'll say enter a celebrity.

1:01:15 And so now basically,

1:01:17 we're creating three variables called color plural noun and celebrity.

1:01:21 And inside of them, we're storing the color that the user enters,

1:01:26 the plural noun, the user enters and the celebrity, the user enters.

1:01:29 So last thing we have to do is replace these guys with those variables.

1:01:34 So I'm basically just going to add in the color over here.

1:01:40 And we're going to add in the plural noun.

1:01:43 So I can just go like this.

1:01:45 And finally, we'll just add in that celebrity.

1:01:50 So now we have a pretty cool mad lib.

1:01:57 And it should be functional.

1:01:59 Everything should work.

1:02:00 It looks like it's good to go.

1:02:02 So let's come over here and we'll run our program.

1:02:06 And then down here in the console, we can play our little mad libs game.

1:02:11 So let's say enter a color, I'm just going to say magenta, enter a plural noun.

1:02:16 Why don't we say microwaves and enter a celebrity, let's say Tom Hanks.

1:02:23 So when I click enter,

1:02:25 what should happen is we should get our mad libs printed out.

1:02:29 So I'm going to click enter.

1:02:30 And now we have our mad libs.

1:02:32 So it says roses or magenta, microwaves are blue.

1:02:35 I love Tom Hanks.

1:02:36 So it's a pretty good mad lib.

1:02:39 And obviously, you know, the more the more print statements we put over here,

1:02:43 you know, the better the mad lib could could be.

1:02:45 And we could store as many, you know, variables up here as we wanted.

1:02:48 This was just a very simple mad lib.

1:02:51 We only took in three inputs, but you know,

1:02:53 you can see how you could take something

1:02:55 like this and create a little mad libs game.

1:02:58 So your homework for this lesson is to go off and make your own mad libs game.

1:03:02 Hopefully one that's a little bit funnier than mine.

1:03:04 But that's the basics of creating a mad libs game in Python.

1:03:13 In this tutorial, I want to talk to you guys about working with lists in Python.

1:03:17 A lot of times when you're programming in Python,

1:03:20 you're going to be dealing with large amounts of data.

1:03:23 And when you're dealing with large amounts of data,

1:03:25 you want to make sure that you can manage it and organize it properly.

1:03:28 And the list is essentially just a structure that we

1:03:32 can use inside of Python to store lists of information.

1:03:35 So we can take a bunch of different data values, we can put them inside a list,

1:03:40 and it allows us to organize them and keep track of them a lot easier.

1:03:44 So generally, you would create a Python list,

1:03:46 and you would put a bunch of related values inside of that list,

1:03:50 and then you can use it throughout your program.

1:03:52 So I'm going to show you guys just the basics of using lists,

1:03:55 we're going to look at some of the common use cases and really

1:03:58 just get you up to speed with what lists are and why they're useful.

1:04:02 So over here in my program, I'm actually going to create a list.

1:04:05 And we create a list a lot like we create a Python,

1:04:09 just like a normal Python variable.

1:04:10 So the first thing we want to do when we're making a list is give it a name.

1:04:15 So we want to give it a descriptive name,

1:04:17 something that's going to basically describe what's inside the list.

1:04:21 In my case, for this example, let's make a list of like friends.

1:04:25 So we could say like here's a list of all my friends.

1:04:28 So I can say friends.

1:04:30 And I'm going to set this equal to the list of values that represent my friends.

1:04:34 And we want to create a list, we can use these open and closed square brackets.

1:04:40 So whenever you use these open and closed square brackets,

1:04:43 Python basically knows,

1:04:44 okay, they want to store a bunch of values inside of this list.

1:04:48 So why don't we go ahead and start adding some values?

1:04:50 So we can say like my friends are like Kevin, Karen, and let's say Jim.

1:04:58 So here I have three values inside of my friends array.

1:05:05 So when we're creating a normal variable in Python,

1:05:09 generally, we just give it one value, right?

1:05:11 So I would create a variable, I would give it one value,

1:05:14 maybe a string or a number or a boolean.

1:05:16 But when we make lists, we're able to store multiple values inside of the same

1:05:22 like little item inside of the same object, right?

1:05:25 And then what I can do is I

1:05:28 can access these individual items inside of my program.

1:05:31 So inside of this friends list,

1:05:33 we're basically storing all of these different values,

1:05:36 and that can be really useful.

1:05:38 So now that we've stored some values,

1:05:40 let's talk about what you can put inside of a list.

1:05:43 So you can really put any piece of information in Python,

1:05:46 we could put things like strings, numbers, or booleans.

1:05:48 So if I wanted, instead of just putting strings here,

1:05:51 I could change like one of these to a number,

1:05:54 and I could change one of these to a boolean,

1:05:56 and it wouldn't matter, Python is going to be fine with that.

1:05:59 But let's change these back to strings just for the sake of the example.

1:06:03 So now that we've created our list,

1:06:06 how can we access individual elements inside of this list?

1:06:09 It's a good question.

1:06:10 I'm gonna go ahead and print something out to the screen.

1:06:13 The first thing we can do is we can just print out the actual list.

1:06:16 So I can just say print friends.

1:06:18 And then when I run this program, if we look down here in the console,

1:06:22 you can see it's just printing out the actual list of friends, right?

1:06:26 But let's say that I wanted to print out a specific element inside of this list.

1:06:31 Well, I can actually refer to elements by their index.

1:06:34 So each one of the elements inside of this list has a particular index.

1:06:39 And the index is actually start at zero.

1:06:42 So we would say that this first element in the list, Kevin has an index of zero.

1:06:47 We would say that this other element Karen has an index of one.

1:06:51 And this third element Jim would have an index of two.

1:06:55 So even though Jim is technically the third element inside of the list,

1:07:00 it has an index of two.

1:07:02 And that's because we start indexing index position one.

1:07:06 And so that's just kind of how lists work.

1:07:09 And that's how list indexes work.

1:07:11 So if I wanted to access a specific element inside of my friends list,

1:07:15 I can just refer to it by its index.

1:07:17 So over here after we type out friends,

1:07:20 I'm just gonna type an open and closed square bracket.

1:07:23 And inside of this open and closed square bracket,

1:07:25 I want to put the index of the element inside the list that I want to access.

1:07:30 So if I wanted to access this guy right here,

1:07:32 this element, I can just put a zero.

1:07:34 So I can say friends zero.

1:07:36 And now when I run my program,

1:07:38 it's just gonna print out that value, it's just gonna print out Kevin.

1:07:42 If I wanted to access this Jim value over here, I can put a two.

1:07:46 And that will give us that Jim value, you can see right there.

1:07:51 So we can access elements based off of their index,

1:07:54 we can also access elements based off of their index from the back of the list.

1:08:00 So for example, if I said negative one inside of here,

1:08:03 this is gonna give me access to this value right here for Jim.

1:08:07 And you can see that sort of does so when we use negatives,

1:08:10 it starts indexing from the back of the list.

1:08:12 So if I said negative two, this is gonna give us Karen.

1:08:15 And so you can use the negatives to access items at the back of the list.

1:08:19 Just keep in mind though, and this is kind of interesting.

1:08:22 We would say this first element here is index position zero, right?

1:08:28 But we would say the first element at the back

1:08:31 of the list is index position negative one.

1:08:33 So just keep that in mind.

1:08:35 So there's actually other ways that we

1:08:37 can access like just portions of this list.

1:08:39 So for example, let's say I just wanted

1:08:41 to select the last two elements in this list.

1:08:43 And I didn't want to select the first one.

1:08:46 Well, in here, I can just say one with a colon.

1:08:49 And this will grab the element at index

1:08:51 position one and all of the elements after that.

1:08:54 So now we should just grab Jim and Karen or Karen and Jim in that order.

1:08:59 I could also specify a range.

1:09:01 So actually, let me add in a couple

1:09:04 other elements just so we can illustrate this better.

1:09:06 So I'll add in two more names.

1:09:08 So if I wanted to, I could select like the element

1:09:11 at index position one up to the element at index position three.

1:09:15 So it's going to grab this one.

1:09:18 So that's one, two.

1:09:19 And it's actually not going to grab the third one.

1:09:22 So it's it's going to grab all the elements up to but not including three.

1:09:25 So it'll grab Karen and Jim.

1:09:27 So let's go ahead and run this.

1:09:29 And you can see it grabs Karen and Jim.

1:09:32 So you can either just put like one with a colon after it,

1:09:35 and then it'll grab that index position and everything after it,

1:09:38 or you can specify like a range that you want to grab from.

1:09:41 So that's how we can access elements inside of this list.

1:09:45 But we can also modify elements.

1:09:47 So for example, I could come down here,

1:09:50 let's say I want to modify this value right here, Karen.

1:09:53 Well, all I have to do is just access that element.

1:09:56 So I could say friends and Karen is at index position one.

1:09:59 And I can change this to whatever I want.

1:10:02 So I could say friends index position one is equal to Mike.

1:10:05 And now when we print out friends index position one,

1:10:09 that value is going to be updated.

1:10:11 So it's just going to say Mike instead of saying Karen.

1:10:14 So it can be really useful to modify values inside of arrays.

1:10:18 So it can be really useful to modify values inside of Python lists.

1:10:23 So those are kind of the basics of working with lists in Python.

1:10:26 And actually in the next tutorial,

1:10:27 I'm going to show you guys even more ways that we can use these lists,

1:10:31 we're going to learn how to like add elements to a list,

1:10:34 delete elements from a list, copy lists,

1:10:35 and a bunch of cool stuff with these lists.

1:10:39 But for now, this has just been sort of like the basics of working with lists.

1:10:47 In this tutorial, I want to talk to you

1:10:50 guys about using functions with lists in Python.

1:10:53 And Python, a list is one of the most

1:10:56 important structures where we can store our information.

1:10:58 A list basically allows you to take a bunch of different values

1:11:02 and organize them and store them inside of their own little list structure.

1:11:06 So down here in my program, you can see I have two lists.

1:11:10 I have a list of lucky numbers.

1:11:11 And this is just a bunch of different numbers.

1:11:13 And then I have a list of friends.

1:11:15 So this could be like a list of somebody's friends.

1:11:17 And it's basically just a bunch of strings with names in them.

1:11:21 So these two lists are storing a bunch of different values.

1:11:25 And what makes lists awesome is not only could I store like this many values,

1:11:28 I mean, I could store hundreds or thousands or millions of values.

1:11:31 And when you're working with a lot of data and a lot of information in Python,

1:11:36 these lists are invaluable.

1:11:38 So because lists are so important,

1:11:40 there's actually a bunch of different functions that we can use with lists.

1:11:44 And those functions allow us to do things like

1:11:47 modify the lists and get information about the list.

1:11:50 So in this tutorial, I just want to show you a bunch of those functions,

1:11:54 we're going to talk about some of the most

1:11:55 common and the most popular functions that you

1:11:58 would use on lists to make them more powerful and make them more easy to use.

1:12:02 So the first thing we can do is obviously just print out a list.

1:12:06 So down here, I'm printing out this friends list.

1:12:09 And when I want to run my program, you see down here,

1:12:13 we're just printing out all the elements in the list.

1:12:15 So it's always good to be able to print out all the elements inside of a list.

1:12:19 But there's a lot of other functions that we can use.

1:12:22 So one function is called the extend function.

1:12:24 And the extend function will basically allow you to take

1:12:28 a list and append another list onto the end of it.

1:12:32 So I could say like friends dot extend.

1:12:35 And inside of these parentheses,

1:12:36 I can pass in the list that I want to add on to the friends list.

1:12:41 So I could say like lucky numbers.

1:12:43 And now when I print out this friends list,

1:12:47 not only is it going to have all the elements in the friends list,

1:12:49 it's also going to have all the elements inside the lucky numbers list.

1:12:52 You can see down here, we have all of our friends.

1:12:55 And then we also have the numbers over here.

1:12:58 So that's a really easy way to essentially just like, add two lists together.

1:13:02 We can also just add individual elements onto a list.

1:13:05 So I could come down here and I could say friends dot append.

1:13:10 And this will actually allow me to append

1:13:14 another item onto the end of this list.

1:13:16 So over here, I could just add another name.

1:13:19 So we could say creed, for example,

1:13:20 and now I'm like adding another friend onto the end of this list.

1:13:24 So when I run the program,

1:13:26 in addition to having the original items that were in the list up here,

1:13:30 we also have this additional item at the end,

1:13:33 and that append function is always going to add

1:13:35 the item onto the end of the list.

1:13:37 But let's say that you wanted to add an item into the middle of the list.

1:13:41 So like right here or right here, there's another list function called insert.

1:13:46 And insert is going to take two parameters.

1:13:49 The first parameter is going to be the index where you want to insert the item.

1:13:54 So why don't we insert it here at index position one?

1:13:57 I'm just going to say one.

1:13:58 And then I'm going to type in the name of the element that I want to add.

1:14:03 So we can just say like Kelly.

1:14:05 And now at index position one, we're going to have the value Kelly,

1:14:08 and all of these other values are going to get pushed up,

1:14:12 they're going to get pushed to the right one index position.

1:14:16 So now I run the program, you can see we have Kevin, this new element Kelly,

1:14:21 and then all the other elements have been pushed off to the right,

1:14:24 we can also remove elements.

1:14:26 So for example, let's say I wanted to remove this gym value,

1:14:30 all I have to do is just say friends dot remove.

1:14:33 And I can just type in whatever element I want to remove.

1:14:37 So I want to remove this gym element.

1:14:39 And so now when we run the program, Jim is going to be gone from the list,

1:14:44 and we just have these four guys left,

1:14:47 you can also remove all of the elements from the list.

1:14:50 So if I just wanted to completely like reset the list and get rid of everything,

1:14:54 I could just say friends dot clear.

1:14:56 And this is going to give us an empty list.

1:14:59 So it'll get rid of every single element inside the list.

1:15:02 There's also another really cool method, which is called pop.

1:15:05 And you can just type out pop like that.

1:15:07 And basically what pops going to do is it's

1:15:09 going to pop an item off of this list.

1:15:12 So when I click the play button,

1:15:14 you'll see here that we're left with Kevin, Karen, Jim, and Oscar.

1:15:18 So we basically got rid of the last element inside the list.

1:15:23 And that's what pop does, it pops an element off of the list.

1:15:26 So it basically removes the last element in the list.

1:15:29 So we have our list, but let's say that we wanted to figure

1:15:32 out if a certain element was in this list, right, if a certain value is in here,

1:15:36 so let's say I wanted to check to see if my friend Kevin was in this list,

1:15:42 well, I could say friends dot index.

1:15:44 And in here, I can just pass a value.

1:15:48 So I could say like, Kevin, and this is going to tell me the index of Kevin.

1:15:54 So it'll tell me if Kevin's in the list.

1:15:56 So now when I click play, you can see down here, it says zero.

1:15:59 If I was to say like Oscar in here,

1:16:02 for example, now it'll give me the index of Oscar.

1:16:05 So that's it three.

1:16:07 But if I put a name that wasn't in here,

1:16:09 so like, if I put Mike, that's not in the list.

1:16:12 And so now we're going to get back in air,

1:16:15 because it says Mike is not in the list.

1:16:18 So that's an easy way to figure out if a specific element is inside of the list.

1:16:22 And if it is, then you know what index it's at, you

1:16:25 can also count the number of similar elements in the list.

1:16:28 So I'm actually going to come down here,

1:16:31 copy this gym element, and we'll add another gym element into here.

1:16:35 So I could come down here and I could say friends dot count.

1:16:40 And we'll pass in gym.

1:16:41 And this will tell me how many times the value gym shows up inside of this list.

1:16:47 So it should say two, which it does down there,

1:16:51 because we have two values with the text gym.

1:16:54 And so we have all these values, we could also sort this list.

1:16:58 So I could come over here and I could say friends dot sort.

1:17:02 And what this will do is it'll sort the list in ascending order.

1:17:06 So we have a bunch of text here, and you'll see what it does.

1:17:11 Basically, what it's going to do is it's going to put it in alphabetical order.

1:17:14 So you can see we have J K O and T.

1:17:17 So the list went from being just random order,

1:17:20 like whatever we had up here to now it's in alphabetical order.

1:17:23 And that's also going to work for lucky numbers.

1:17:26 So I could say like lucky numbers dot sort,

1:17:29 and then we'll print out lucky numbers.

1:17:32 And these should now be in ascending order,

1:17:35 which I'm realizing they already are up here.

1:17:38 But if I was to take this 42 and put it down here,

1:17:42 now it will figure everything out and put it in ascending order.

1:17:47 Anyway, we can also reverse a list.

1:17:49 So if I wanted, I could reverse this lucky numbers list,

1:17:53 I could say lucky numbers dot reverse.

1:17:55 And now when we print it out,

1:17:58 instead of being 4815 1623, it's going to be 2316 15 842.

1:18:03 So it's basically just reverse the order of the list.

1:18:06 And finally, there's one more list function I

1:18:09 want to show you guys which is copy.

1:18:12 So I could actually create another list, and I could make it as a copy.

1:18:17 So I could say like,

1:18:19 friends to, and we could set this equal to friends dot copy.

1:18:23 And now friends to is going to have all the same attributes as friends.

1:18:30 Because it's basically just like copied it

1:18:33 basically took a copy of that friends list.

1:18:35 So you can see it's the same exact thing and copying

1:18:38 lists can come in handy in a lot of different situations.

1:18:40 So those are just some basic list functions and just to kind of like,

1:18:44 you know, get your feet wet and working with lists.

1:18:47 Obviously, like the more you work with them,

1:18:49 the more you practice using these different functions,

1:18:51 the more comfortable you're going to get.

1:18:52 But that's just kind of like a basic overview of what you can do.

1:18:55 In this tutorial, I want to talk to you guys about tuples in Python.

1:19:03 Now a tuple is a type of data structure,

1:19:08 which basically means it's a container where we can store different values.

1:19:13 Now if you're familiar with lists in Python,

1:19:16 a tuple is actually very similar to a list.

1:19:19 It's basically a structure where we can store multiple pieces of information.

1:19:24 But a tuple has a few key differences from lists

1:19:29 that we're going to talk about in this tutorial.

1:19:31 First thing I want to do is I want to show you the how to create a tuple.

1:19:35 So I can come down here and I can create a tuple.

1:19:38 And one of the most common examples of tuples is coordinates.

1:19:42 So let's say I had a series of like XY coordinates,

1:19:46 I could create a variable called coordinates.

1:19:48 And I'm just going to set this equal to an open and closed parentheses.

1:19:53 And whenever we want to create a tuple inside of Python,

1:19:57 we're going to use these open and closed parentheses.

1:20:00 And inside of here inside of these parentheses,

1:20:02 we're going to put the values that we want to store.

1:20:06 So I could, for example, put a list of numbers.

1:20:09 So this could be like my coordinates, I could have like four and five.

1:20:14 So this would be my tuple with coordinates inside of it.

1:20:18 And one of the things about tuples

1:20:21 that makes them unique is a tuple is immutable.

1:20:24 And you'll hear that word a lot when we're talking about tuples immutable,

1:20:27 it basically means that the tuple can't be changed or modified.

1:20:31 Once we create our tuple up here, you cannot modify it,

1:20:35 you cannot change it, you can't add elements to it,

1:20:38 you can't erase elements from it,

1:20:40 you can't change any of the elements inside the tuple.

1:20:43 What you see is what you get, once you create the tuple,

1:20:46 it's, it's as it is, it can't change.

1:20:48 So I could come down here and I can

1:20:50 print out some of the attributes inside the tuple.

1:20:54 And the way I can access them is just by using an open enclosed square bracket.

1:21:00 And in here, I can pass in a index.

1:21:04 So tuples are indexed starting at zero.

1:21:07 So technically, we would say that four is at index position one and sorry,

1:21:12 four is at index position zero and five is at index position one.

1:21:16 So if I said coordinate zero, now it should print out four.

1:21:21 And down here, we're printing out four.

1:21:23 So if I wanted to print out that five,

1:21:27 we can just put a one inside of those square brackets.

1:21:29 And now we'll print out that five.

1:21:31 So I can access the elements inside of a tuple,

1:21:34 I can easily access each, each entry.

1:21:37 But if I was to come over here and try to change one of the elements,

1:21:43 so if I said coordinates, and coordinates one,

1:21:46 and I tried to set it equal to something else like 10,

1:21:50 Python's actually going to give us an error when we run this program.

1:21:53 So I'm going to run the program, you see we get this error, it says,

1:21:57 type error tuple object does not support item assignment,

1:22:02 because it's immutable, because we can't change it.

1:22:06 So that's basically what tuples are how we can create them.

1:22:10 And you know, a tuple, like I said, it's very simple,

1:22:13 you just create it, and then you have it.

1:22:15 And now I want to talk to you guys about a common topic in Python,

1:22:19 which is the difference between tuples and lists.

1:22:23 So remember, a list is basically doing the same thing a list.

1:22:25 If we wanted to create a list,

1:22:27 we would just use square brackets instead of those parentheses.

1:22:30 And if I was using a list, I could assign different values to it,

1:22:35 I could I could basically mutate any of the elements I could add delete,

1:22:40 modify change, whatever I wanted with the list.

1:22:43 But with a tuple, we can't do that.

1:22:45 And that's sort of the basic difference.

1:22:48 And really, Python doesn't say anything more than that.

1:22:51 It basically just says like one of them's immutable, one of them's not.

1:22:55 But in practical use cases, generally,

1:22:57 people will use tuples for data that's never going to change.

1:23:01 So you'll you'll store data inside of a tuple,

1:23:04 when that data doesn't need to be mutated.

1:23:07 That's why something like coordinates is such a good candidate for a tuple,

1:23:12 because once you have coordinates,

1:23:13 like, we're probably not going to modify them,

1:23:15 right, we might add other coordinates.

1:23:17 So for example, if I wanted, I could create a list of tuples.

1:23:22 So I can say like 4567, maybe we have some other coordinates, like 8034.

1:23:28 So here I have, you know, I have a list and inside of it, we have these tuples.

1:23:36 But remember, these tuples can't be modified, the values can't be changed.

1:23:40 So really, it's just a case by case basis, I would say by a huge majority,

1:23:45 you're going to be using lists most of the time.

1:23:48 Tuples are more of a niche, you know, they're using more special situations.

1:23:54 But there are plenty situations where you want to use tuples.

1:23:56 So if you're in a situation where you want

1:23:58 to store data that can't be changed or mutated, then tuples are the way to go.

1:24:03 So yeah, that's just some basics about tuples,

1:24:05 some basics about the difference between lists and tuples.

1:24:08 And so a tuple is a great thing to add into your Python repertoire.

1:24:14 In this tutorial, I want to talk to you guys about using functions in Python.

1:24:22 Now a function is basically just a collection of code,

1:24:27 which performs a specific task.

1:24:28 So I can take a bunch of lines of code that are basically doing one thing,

1:24:33 I can put them inside of a function.

1:24:35 And then when I wanted to do that task

1:24:38 or do that one thing that the function was doing, I can just call the function.

1:24:43 And so functions really help you to organize your code a lot better,

1:24:47 they allow you to kind of break up your code into different,

1:24:50 you know, little chunks that are doing different things.

1:24:53 And they're really just awesome.

1:24:54 So functions are like a very core

1:24:56 concept when we're talking about programming in Python.

1:24:59 So I'm going to show you guys how to create an awesome function today.

1:25:03 Let's say for the purposes of this tutorial,

1:25:05 we want to create a function that says hi to the user.

1:25:09 So the one task that our function performs is

1:25:12 basically just saying hi to whoever is writing the program.

1:25:15 So over here, if I want to write a function,

1:25:19 the first thing I have to use is a keyword in Python, it's called death.

1:25:23 So D E F.

1:25:25 And basically, when Python sees this keyword, it's going to say,

1:25:29 okay, this person wants to use a function.

1:25:32 So after we type out death, we need to give this function a name.

1:25:37 So just like when we are creating variables, we give them descriptive names,

1:25:43 we also want to do the same thing with functions.

1:25:46 So if I'm creating a function, I can just give it a specific name,

1:25:50 which basically says like what it's doing.

1:25:51 So we're going to create a function that says hi.

1:25:54 So I'm just going to call this function, say hi, just like that.

1:25:59 And once we type out the name of the function,

1:26:02 and so also I could type out say hi with no

1:26:05 underscore or I can type out say hi with an underscore,

1:26:08 both are considered like good practices in Python.

1:26:11 A lot of times, if you just have a simple like

1:26:14 two word function like this, you don't need to put an underscore,

1:26:17 but we could put an underscore there.

1:26:19 If we wanted, after we type out the name of the function,

1:26:22 I'm just going to type an open and close parentheses.

1:26:25 And then I'm going to type a colon.

1:26:27 And basically, what this is doing is it's saying to Python, like, all right,

1:26:32 all the code that comes after this line is going to be inside of our function.

1:26:37 And in order to write code that's going to end up being inside the function,

1:26:42 we actually have to indent it.

1:26:44 So over here, you'll notice that when I clicked enter,

1:26:47 my text editor automatically indented the text.

1:26:50 So it's automatically like, using this indent here.

1:26:54 And that's kind of like one of the rules in Python is like,

1:26:58 the code that goes inside of this function needs to be indented.

1:27:01 So if I was to write some code, like out here,

1:27:05 this is no longer going to be considered inside the function.

1:27:08 So you can see, as I type out code, and obviously,

1:27:11 this isn't real code, but as I type text over here,

1:27:14 that's indented, this little like marker over here is basically saying like,

1:27:18 Oh yeah, that's inside the function.

1:27:20 But then when I write code over here,

1:27:23 that is like not at the same indentation level as this stuff,

1:27:27 it's no longer considering it inside the function.

1:27:29 So that's just a little thing.

1:27:31 Any code inside this function needs to be indented.

1:27:33 Alright, so our function is just going to say hi to the user.

1:27:37 So I'm just going to have it print out some text, it's going to say hello, user.

1:27:43 So this is a very simple function.

1:27:46 Obviously, we just have one line of code and inside of a function,

1:27:49 you could have, you know, as many lines of code as you want.

1:27:52 But for our purposes, we only need one line in order to perform our function.

1:27:57 So now all we have to do is call this function.

1:28:00 So if I want to execute the code inside of this function,

1:28:03 I have to do something called calling it.

1:28:06 So if I was to just run my program as it is right now,

1:28:10 I'm just going to run it, you'll see that nothing happens over here, right?

1:28:15 Even though this function is printing out hello user,

1:28:17 when I run the program, it's not doing it.

1:28:20 And that's because the code inside of a function

1:28:23 isn't going to get executed by default.

1:28:25 The code inside of a function is only going to get

1:28:29 executed when we specify that we want to execute it.

1:28:31 And in order to do that, we're going

1:28:33 to have to do something called calling the function.

1:28:35 So in order to call the function, you basically just type out the functions

1:28:39 name and those open and close parentheses.

1:28:41 So I'm just going to type out say hi, and open and close parentheses.

1:28:46 And now when we run this program again,

1:28:49 you'll see that it prints out hello user.

1:28:51 So we're executing the code inside of the function.

1:28:54 And I want to show you guys just one more thing here,

1:28:58 just talking to you guys about how these functions actually work.

1:29:01 So up here, I'm going to print top.

1:29:04 And then down here, I'm going to print bottom.

1:29:07 So I want to show you guys the flow of these functions inside the program.

1:29:11 So when I run this program,

1:29:14 you'll see we print out top hello user, and then bottom.

1:29:19 So essentially, what's happening is when

1:29:21 Python goes through and executes this program,

1:29:24 it goes over here to this first line, it says,

1:29:27 okay, we want to print out the word top.

1:29:29 And then it goes down here and it says,

1:29:32 okay, we want to execute the say hi function.

1:29:35 So Python actually jumps up, and it goes over to this say hi function,

1:29:40 and it's going to execute all of the code inside of this function.

1:29:44 So it's going to go through execute all this code.

1:29:46 And then once it's done executing all the code in the function,

1:29:50 it's going to jump back down here,

1:29:51 and it's going to move on to the next line, which is bottom.

1:29:54 So that's kind of like the flow of functions.

1:29:57 Again, with functions generally, when we're naming these functions,

1:30:01 you want them to be named in all lowercase.

1:30:05 And usually, when we're naming stuff in Python, if there's two or more words,

1:30:09 we're going to use an underspace or an underscore in between them.

1:30:13 So I could write this out as say underscore high.

1:30:16 But in a lot of situations, though,

1:30:17 if I have a function like this where the name is really short,

1:30:21 I might just be easier to leave it without an underscore,

1:30:23 but why don't we just put an underscore

1:30:24 in there just to be a super Python official.

1:30:27 All right, so now we can actually

1:30:30 make these functions a little bit more powerful.

1:30:33 And what we can do is we can give them information.

1:30:36 So a lot of times when we write a function,

1:30:39 we're going to want to have additional information that gets passed in.

1:30:43 And these are called parameters.

1:30:45 So a parameter is a piece of information that we give to the function.

1:30:51 So over here, I can actually specify

1:30:53 that this function needs to receive some parameters.

1:30:56 So I can basically say like, Hey, if you're going to call this function,

1:31:00 you need to give us some information, you need to give us some parameters.

1:31:03 And all I have to do to do that is just

1:31:05 type out the name of the parameter that I want to receive.

1:31:09 So why don't we allow the code calling this function

1:31:13 to tell it what name to say hi to up here, I can just say name.

1:31:17 And basically, what this means is it means whenever I call this say hi function,

1:31:21 we have to give it a name.

1:31:23 So down here, if I was to call this, I have to include a name in here.

1:31:28 So I can say like, Mike, and what we can do now is we can actually

1:31:32 access this parameter or this variable inside of our function.

1:31:36 So I could come over here and instead of saying hello user,

1:31:40 I could say hello name.

1:31:42 And basically, what this is going to do is it's just

1:31:45 going to say hello to whatever name got passed in here.

1:31:49 So I'm actually going to copy this and we will do this twice.

1:31:53 So I'll say hello, Mike hello, Steve.

1:31:56 And now when I run this program,

1:31:59 you'll see that instead of just saying hello user,

1:32:03 it's saying hello to whichever name I passed into the function.

1:32:06 So that's why this can be really useful, right?

1:32:09 We can give the function information,

1:32:10 and depending on the information we give it,

1:32:13 it'll perform its task a little bit differently.

1:32:15 I could also include more than one parameter.

1:32:18 So you can, I mean, technically,

1:32:20 you could have like as many parameters as you want.

1:32:22 So I can put another one in here, we can say age.

1:32:25 And now I'm going to have to pass in an age along with these.

1:32:29 So I'm just going to pass in age and pass in an age for down here.

1:32:34 And I'm just going to pass in strings.

1:32:37 So we can say hello name.

1:32:43 You are age.

1:32:44 So I'm passing in two pieces of information.

1:32:47 And now when we run this program, it's going to call the function.

1:32:51 And it's going to use both of those pieces of information.

1:32:54 So I say hello, Mike, you are 35.

1:32:57 Hello, Steve, you are 70.

1:32:59 So essentially, we're writing out this one line of code,

1:33:03 which just prints out like hello to someone.

1:33:06 And we're allowing this function to receive two parameters.

1:33:09 So the name and the age, and depending on the name and the age,

1:33:13 the function's going to print out hello a little bit differently.

1:33:16 And that's kind of the beauty of using function.

1:33:19 So you could pass anything you want into a function.

1:33:22 So for example, I could pass in a integer instead of a string for the age.

1:33:27 So like I could pass in the number, the only difference is over here,

1:33:31 we're going to have to convert this into a string.

1:33:34 But it's going to work just the same.

1:33:37 So you could pass in strings, numbers, bullions, arrays,

1:33:41 you can really pass any type of data into a function.

1:33:46 And it's going to work.

1:33:47 So you can see here, we get the same result.

1:33:49 So that's the basics of functions.

1:33:51 And as you go through with Python,

1:33:53 you're going to be using functions more and more.

1:33:56 And generally, it's a good idea to break your code up into different functions.

1:34:00 So whenever you have like a grouping

1:34:03 of code that's designed to perform a specific task,

1:34:06 that's usually a good candidate to be put inside of a function.

1:34:11 In this tutorial, I want to talk to you

1:34:15 guys about using the return statement in Python functions.

1:34:19 Now Python function is basically just a collection

1:34:23 of Python code that performs a specific task.

1:34:26 And when we want to perform that task in our Python programs,

1:34:30 we can call a Python function.

1:34:32 And a lot of times when we're calling a Python function,

1:34:36 we just kind of call it and it does its thing.

1:34:38 And then we move on with the program.

1:34:40 But sometimes when we call a function,

1:34:42 we're actually going to want to get information back from that function.

1:34:47 So when I call the function, I want it to basically execute its task,

1:34:50 I want it to execute all the code.

1:34:52 And then I want it to like give me some information back.

1:34:55 So that could be like a particular value,

1:34:57 it could be something like telling me how the task went.

1:35:00 Basically, the function can just communicate back to us like,

1:35:04 Hey, here's some information.

1:35:05 And that's what the return keyword can allow us to do

1:35:09 the return keyword can basically allow

1:35:12 Python to return information from a function.

1:35:14 So I'm going to show you guys how we can

1:35:17 do this, I want to create a very simple function.

1:35:20 And it's just going to cube a number.

1:35:22 So when we cube a number, we take it to the power of three.

1:35:26 So if I was going to cube like two,

1:35:28 it'd be like two raised to the power of three.

1:35:31 Right, it's just pretty basic math.

1:35:33 So we're going to make a function that will cube a number.

1:35:36 And I'll show you guys how we can use that return statement.

1:35:39 So first thing we want to do is make a function,

1:35:42 I'm just going to say death cube, we'll call the function cube.

1:35:46 And over here, we can specify any parameters that this function will take.

1:35:51 So basically, any values that we want to give this function.

1:35:55 So we're going to give it one function, which is just going to be a number.

1:35:58 So I'm just going to call it num.

1:36:00 And then over here, I'm going to type out a colon.

1:36:03 And then down here, we can put any of the code

1:36:06 that we want to be included in this function.

1:36:09 So basically, this function is just going to cube this number.

1:36:12 So we could just type out num, times num, times num.

1:36:16 Right, that's going to give us num cubed.

1:36:20 So that's all well and good.

1:36:22 And if I come down here, I can execute this function.

1:36:25 So I can basically just call it, I'll say cube.

1:36:28 And why don't we pass it a three?

1:36:30 So I'm going to go ahead and pass it to three.

1:36:33 And I'm going to save this.

1:36:35 And now let's go ahead and run this code.

1:36:39 So we're on the code.

1:36:41 And you'll see down here, nothing happened, right?

1:36:45 So nothing got printed out in our program.

1:36:48 In fact, when we call this cube function, it didn't really do anything.

1:36:52 So let me try to print this out.

1:36:55 So maybe if we print this function out,

1:36:57 it'll give us back the information that we want.

1:37:00 So type out print, and we'll print out the value of the function,

1:37:04 I'm just going to click play.

1:37:05 You look down here, it says none.

1:37:08 So when I printed out the value of this function, it told me none.

1:37:13 But really, this function is supposed to be cubing the number.

1:37:17 And here's how we can use the return statement in Python.

1:37:20 I can come over here and I can just say return.

1:37:24 And now Python is going to return whatever value we put over here to the right.

1:37:28 So when I call this cube function, and I give it a three,

1:37:32 Python is going to go off, it's going to execute this function.

1:37:36 When it sees this return statement, it's going to say, okay,

1:37:39 I want to give a value back to whatever call of this function.

1:37:43 And it's going to return this value.

1:37:46 Now, when I print out cube three,

1:37:49 it should print out the answer because we get an answer back.

1:37:53 So when I play this, you'll see down here, it says 27.

1:37:57 So we got the correct answer.

1:37:59 So I could do this with anything, why don't we cube like four or something?

1:38:02 So now we're on this.

1:38:04 And you can see we're constantly getting the correct answer back.

1:38:09 So that's the basics of using this return statement,

1:38:11 it allows us to return a value back to the caller.

1:38:15 In other words, back to whatever's calling the function.

1:38:17 So I just want to illustrate this point a little bit further,

1:38:21 I'm going to come up here, I'm actually going to create a variable.

1:38:23 So I'm going to create a variable called result.

1:38:26 And I'm just going to set it equal to cube four.

1:38:30 This variable result is going to store

1:38:33 the value that gets returned from the cube function.

1:38:36 So it's not going to store like cube four,

1:38:39 it's going to store the value that gets returned from executing that function.

1:38:43 So now if I came down here and printed out result,

1:38:46 it's actually just going to print out 64 again,

1:38:49 because that's the value that it's storing.

1:38:51 So this return statement can be really useful

1:38:53 for like getting information back from a function,

1:38:56 we can use something like a parameter, like this four as a parameter,

1:39:00 and we can give information to a function.

1:39:02 And then we can use the return

1:39:05 statement to get information back from a function.

1:39:07 And I do just want to point out one more thing,

1:39:11 I'm actually not able to put any code after this return statement.

1:39:15 So if I came down here and tried to put like a print statement,

1:39:19 this actually isn't going to work.

1:39:20 So this is never going to get printed out.

1:39:23 So if I just typed out like code right here,

1:39:26 when we run this program, it's not going to type out code.

1:39:30 That's because when I use this return keyword, it breaks us out of the function.

1:39:36 So Python's going to go through, it's going to execute the code in the function,

1:39:40 whenever it sees this return keyword,

1:39:41 it's just going to break back out and we're going to be done.

1:39:45 So we'll never be able to reach this line of code.

1:39:48 So that's the basics of using return statements.

1:39:51 And you can return any data type you want,

1:39:53 we could easily return like a string or a Boolean or an array,

1:39:57 it doesn't really matter, you can return whatever you want.

1:40:00 And a lot of times in a lot of situations,

1:40:02 you're going to want to get a value back from a function.

1:40:09 In this tutorial, I want to talk

1:40:11 to you guys about using if statements in Python.

1:40:14 Now if statements are a special structure in Python,

1:40:17 where we can actually help our programs to make decisions.

1:40:21 So by using an if statement,

1:40:23 I could execute certain code when certain conditions are true.

1:40:27 And I can execute other code when other conditions are true.

1:40:31 So basically if statements allow our programs

1:40:33 to respond to the input that they're given.

1:40:36 So depending on the data that we're using in the program,

1:40:40 our programs will be able to respond.

1:40:42 So when certain data is certain values, we can do certain things.

1:40:46 And when other data is other values, we can do other things.

1:40:49 So you know, your programs are essentially becoming a lot smarter.

1:40:53 And actually, if statements are things that we

1:40:56 as human beings deal with every day.

1:40:58 So you know, as you go throughout your day,

1:41:01 generally, you're dealing with if statements all the time.

1:41:03 So I want to kind of give you guys a brief introduction into if statements,

1:41:07 and we'll talk about some of the common

1:41:09 if statements that you'd see in everyday life.

1:41:11 And then we'll go ahead and do a really awesome example to kind

1:41:14 of like show you guys what if statements can do for us.

1:41:17 So over here in my text editor, I just have this little text file.

1:41:21 And in here, I wrote out a bunch of if statements

1:41:24 that a lot of people will encounter on a daily basis.

1:41:27 So here's the first one, it says I wake up, if I'm hungry, I eat breakfast.

1:41:33 So let's break this down a little bit up here, it says if I'm hungry.

1:41:38 And this is a condition, right?

1:41:39 This is either going to be true, or it's going to be false, right?

1:41:44 If it's true, I'm going to go ahead and eat breakfast, right?

1:41:48 If it's false, I'm just going to skip whatever was in here and move on, right?

1:41:53 So that's the basics of an if statement, right?

1:41:55 We have a condition, in this case, if I'm hungry,

1:41:58 if the condition is true, then we do the action.

1:42:02 So we eat breakfast.

1:42:03 Otherwise, we just skip it.

1:42:05 So down here, we have another one, it says I leave my house.

1:42:10 If it's cloudy, I bring an umbrella.

1:42:13 Otherwise, I bring sunglasses.

1:42:14 And so this one is a little bit more complex than the one we just looked at.

1:42:19 You'll see we have our condition, right?

1:42:21 It says if it's cloudy, if that condition's true,

1:42:24 we're going to bring the umbrella.

1:42:26 But in this case, if the condition's false,

1:42:29 there's something else that we want to do.

1:42:31 So in the case up here, if this condition was false, we just moved on.

1:42:35 But now if this condition's false,

1:42:37 then we're going to go ahead and bring sunglasses.

1:42:40 So that's another example of an if statement, it's a little bit more complex.

1:42:44 Finally, I have one more down here,

1:42:46 and this one's even more complex, it says I'm at a restaurant.

1:42:50 If I want meat, I order a steak.

1:42:52 So if this condition's true, we order the steak.

1:42:55 But if this condition is false, then we're going to move on, and we're

1:43:00 actually going to check another condition.

1:43:02 So I'm going to say otherwise, if I want pasta, I order spaghetti and meatballs.

1:43:07 This is another condition.

1:43:08 If this condition's true, we get the spaghetti.

1:43:11 If it's not true, then finally, we're going to move on down here,

1:43:16 and we'll just default to ordering the salad.

1:43:18 So all three of these if statements are valid if statements,

1:43:22 it's just they get more and more complex as we go down the list.

1:43:26 So hopefully that's, you know, it can kind of wrap your head around

1:43:29 what if statements are we're basically specifying conditions.

1:43:31 If those conditions are true, we're going to do certain things.

1:43:35 And if those conditions are false,

1:43:37 we can do other things, or we can check other conditions.

1:43:40 All right, so let's head over to our Python file,

1:43:43 and we'll start writing some actual Python.

1:43:45 So in here in my app dot Python file, I want to create an if statement.

1:43:50 And I'm going to show you guys a very basic if statement in this tutorial.

1:43:53 And then in the next tutorial,

1:43:55 we're going to look at some more advanced if statements.

1:43:58 And so what I want to do is create a Boolean variable.

1:44:02 So I'm going to create a Boolean variable that's going

1:44:05 to store whether or not the user is a mail.

1:44:07 So it's just going to be called is underscore mail.

1:44:10 And I'm going to set this equal to true, because I'm a male.

1:44:14 So we have this Boolean variable, right?

1:44:16 And right now we have it set equal to true.

1:44:20 I can actually use an if statement to check

1:44:23 to see what the value of this variable is.

1:44:26 And if it's true, I can do something.

1:44:27 So if I want to use an if statement, all I have to do is just type out if,

1:44:32 and then I just need to type out a condition.

1:44:36 So basically, I would have to type out

1:44:38 like something that's going to be true or false.

1:44:41 Like, for example, in the other page, we were specifying like, if I'm hungry,

1:44:46 or if it's cloudy, here, we're just going to check to see if is mail.

1:44:50 So in other words, if the person is male.

1:44:53 And so remember, this has to be a, like,

1:44:56 it has to be able to be reducible to a true or a false value.

1:45:01 So in our case, we're just using a Boolean,

1:45:03 because that's like the easiest thing we can do.

1:45:06 So I said if I specified my true or false condition,

1:45:11 and now I want to just type a colon.

1:45:13 And what I want to do now is make a new line.

1:45:16 And so anything that I put below this with an indentation

1:45:20 is actually going to be executed when that conditions true.

1:45:25 So I could put print.

1:45:26 And down here, I could just put you are a male.

1:45:32 And now you'll see what happens when I run this program,

1:45:34 it's going to go down here, and it's going to say you are a male.

1:45:38 But if I changed is mail to false.

1:45:41 So instead of this being true, I just change it to false.

1:45:44 Now all of a sudden it's not going to print anything.

1:45:47 So it's just going to be blank down here.

1:45:50 That's because this condition wasn't true.

1:45:53 So anything that I put below this if declaration and that has an indentation

1:45:58 like that is going to be executed when the if statement is true.

1:46:03 We can also use another keyword in Python, which is called else.

1:46:08 And else is basically going to be like otherwise.

1:46:11 So you remember before we said, if it's cloudy, I'll bring an umbrella.

1:46:15 Otherwise, I'll bring sunglasses.

1:46:17 Well, this is going to be like our otherwise.

1:46:20 So I can say down here else.

1:46:22 And now anything that I put below else is

1:46:25 going to get printed out when that condition isn't true.

1:46:28 So why don't we just put you are not a male.

1:46:32 So now we're able to cover both of the situations for this variable.

1:46:36 If it's false, we can cover that situation.

1:46:39 So it says you are not a male.

1:46:41 If it's true, we can cover that situation as well.

1:46:45 So it'll say you are a male.

1:46:47 So that's pretty cool.

1:46:49 But we can also make these more complex.

1:46:52 And actually before I talk about that, you can put

1:46:55 as much code as you want inside of an if statement.

1:46:57 So I could have like, you know, dozens of lines of code if I wanted.

1:47:01 I'm just giving you guys a very simple example.

1:47:03 So why don't we make this more complex?

1:47:06 And I'm going to add another variable into the mix.

1:47:09 So I'm going to add another, you know, Boolean attribute into this mix.

1:47:13 I'm going to make another variable called is tall.

1:47:15 And we're going to set this equal to true as well.

1:47:19 So now I have two variables in the mix.

1:47:22 Let's say I wanted to write an if

1:47:25 statement that will check both of those variables.

1:47:27 So I could write an if statement that's like,

1:47:30 if they're male and they're tall, or if they're male and they're not tall,

1:47:33 or if they're not male and they're tall, like I could write out a bunch of if

1:47:37 statements to check the combination of these variables.

1:47:40 And so the way I can do that is by using one of two keywords.

1:47:45 So the first keyword I want to show you guys is the or keyword.

1:47:50 So I can come over here and I can say if is male, or is underscore tall.

1:47:56 And what this is basically going to do is

1:47:59 it's going to say if the person is either male,

1:48:03 or if they're tall, then we want to do something.

1:48:06 So this is only going to be true when one of these values is true,

1:48:12 when one or both of those values is true.

1:48:15 So down here, we could actually put instead of you are a male,

1:48:19 we could put you are a male or tall or both,

1:48:22 that's going to be more appropriate.

1:48:24 And then down here, we would say you are neither male nor tall.

1:48:31 And that's because if we execute the code inside of this else,

1:48:36 that means that both of these guys are false.

1:48:39 Right, so I'm saying if they're male or they're tall,

1:48:42 we're going to execute whatever is in here.

1:48:45 Otherwise, that means they're neither male nor tall.

1:48:47 We're just going to execute this down here.

1:48:50 So let me show you guys how this works.

1:48:52 I'll click play.

1:48:53 And these are both true.

1:48:54 So it's going to say you are a male or tall or both.

1:48:57 If I was to set one of these to false.

1:49:00 So let's set is male equal to false.

1:49:02 Now, it's still going to say you are a male or tall or both.

1:49:07 But if I set them both equal to false,

1:49:10 now it's going to say you're neither male nor tall.

1:49:14 So that's kind of the basics of using the or operator.

1:49:19 And there's another operator we can use which is called and, and basically

1:49:24 it's similar to or except both of these conditions have to be true.

1:49:28 So this is basically saying if the person is male and they're also tall,

1:49:34 then we're going to execute whatever is in here.

1:49:36 So we could actually change this text to say you are a tall male,

1:49:40 because we know for a fact that if this is getting executed,

1:49:45 they're both male and tall.

1:49:47 We can also change this print statement down here.

1:49:50 This could say you are either not male or not tall or both.

1:49:56 So you can see it's basically just saying that you're

1:50:00 either not one of them or you're not both of them.

1:50:04 So we click the play button and you'll see because they're both false,

1:50:08 it's going to say you are either not male or not tall or both.

1:50:12 But if I make them both true, now it's going to say you are a tall male.

1:50:17 If I was going to make one of these false, though, so let's make is tall false.

1:50:23 Now it's not going to execute this first print statement.

1:50:27 It's going to execute the one inside of the else.

1:50:29 So to say you are either not male or not tall or both.

1:50:32 So that's the basics of and an or and you'll

1:50:36 be using those a lot as you use your if statements.

1:50:39 But there's actually one more thing we can do.

1:50:42 We can add in some more conditions.

1:50:45 So up here I'm checking if they're male and they're tall.

1:50:48 But what if I wanted to check if they're and they're not tall?

1:50:52 So if they're like a short male, I can use another keyword in Python called

1:50:58 else if or really it's just typed out E

1:51:00 L I F and it stands for else if and after this we can put another condition.

1:51:05 So over here I want to check to see if they're male and they're not tall.

1:51:11 So I'm going to say else if male is male and now I can type in not tall

1:51:17 and the way I can do that is by saying

1:51:20 not an open and close parentheses and saying is tall.

1:51:23 And basically when I use this not function

1:51:26 it's going to negate whatever is inside of here.

1:51:29 So if this was true it's going to make it false

1:51:32 and if this was false it's going to make it true.

1:51:35 So basically that'll tell us whether or not they're tall.

1:51:38 And then I'm going to use a colon

1:51:41 and now down here inside of here we're basically

1:51:44 just going to type out any of the code

1:51:47 that we want to happen when this condition's true.

1:51:49 So down here we can just print out you are a short male and there's actually one

1:51:56 more condition that we want to check for which

1:51:59 would be if they're not male and they're tall.

1:52:02 So we can make one more else if and I'm actually

1:52:06 just going to copy this guy and we'll paste it down here.

1:52:10 And so I want to say if not is male and is tall.

1:52:16 So now we're checking to see if they're male

1:52:20 and or if they're not male and they're tall.

1:52:24 So here we could say you are a you are not a male but are tall.

1:52:32 So essentially here we have an if statement that's

1:52:35 going to cover every single condition for these two variables.

1:52:38 So in every single situation of the two values of these variables

1:52:42 we're going to be able to print something out for it.

1:52:45 So if I made both of these true it's

1:52:48 basically going to tell us you are a tall male.

1:52:51 If I make is male false it's going to tell us you are not a male but are tall.

1:52:57 If I made is male true and is tall false

1:53:01 then it's going to tell us you are a short male.

1:53:05 And if I made both of these false it's going to tell

1:53:09 us you are either not male or not tall or both.

1:53:12 And actually we need to change this.

1:53:15 So this should say you are not a male and not tall.

1:53:19 So that would be a better print out for that situation.

1:53:23 So you can basically see how we can use if else ifs and else in order

1:53:30 to help our program to make decisions and really

1:53:33 to respond to the different data in our programs.

1:53:36 So I'm able to respond to every

1:53:38 combination of the values for these two variables.

1:53:41 And that's really cool.

1:53:43 So in this example we were just using simple Boolean variables but in the next

1:53:48 tutorial I'm going to show you guys how

1:53:50 you can actually use something called comparison operators.

1:53:53 So we could compare like two numbers or two

1:53:56 strings and we could use those as our conditions.

1:53:58 But for now I think this is a good introduction into if statements.

1:54:03 So I'll see you guys in the next tutorial.

1:54:08 In this tutorial I want to talk to you some more about if statements in Python.

1:54:14 More specifically we're going to be looking

1:54:16 at using comparisons inside of our if statements.

1:54:19 So if you're following along with the course

1:54:21 in the last tutorial I talked to you guys about just the basics of if statements

1:54:26 and we used a couple different Boolean variables.

1:54:28 And depending on the values of those bullions we were able to do certain things.

1:54:32 In this tutorial we're going to look at another

1:54:35 way to use if statements which is with comparisons.

1:54:37 So instead of just using Boolean

1:54:40 values we can actually compare different values.

1:54:43 So I could compare a couple numbers or I could compare a couple strings.

1:54:47 And depending on the results of those comparisons we can do certain things.

1:54:51 So this is going to be pretty cool.

1:54:54 And this is really going to give you guys

1:54:56 a full understanding of what you can do with if statements.

1:55:00 So for this tutorial I actually want to create a Python function.

1:55:04 And this function is going to give us the maximum number that we pass into it.

1:55:09 So this function is going to take three parameters as input

1:55:13 and it's going to print out the biggest number that we give it.

1:55:18 So let's create this function.

1:55:19 I'm just going to say death.

1:55:22 And I'm just going to call it max num.

1:55:25 And inside of these parentheses I'm going

1:55:28 to specify that I want three parameters as input.

1:55:31 So I'm going to say num one, num two and num three.

1:55:35 So basically we're passing it three numbers

1:55:38 and this function will return the largest of the three.

1:55:43 So in order to figure out which of these numbers is

1:55:46 the largest we're going to have to use an if statement.

1:55:49 So I can say if and over here I need to specify a condition

1:55:53 right so I need to put like a true or a false value.

1:55:57 And so what we can actually do is we can compare these different numbers.

1:56:01 So I could say if num one is greater than or equal to num two.

1:56:09 And num one is greater than or equal to num three.

1:56:14 So basically what I'm doing here is I'm comparing these different numbers.

1:56:18 So I'm saying if the first number is greater than or equal to the second number.

1:56:23 And this is a comparison.

1:56:24 So when you think about it, when we compare these two numbers,

1:56:28 we're going to end up with a true or a false value.

1:56:31 Right, num one is either greater than or equal to num two or it's not.

1:56:36 It's actually a Boolean value right it's either true or it's false.

1:56:40 Same thing over here.

1:56:42 The result of this comparison is either true or it's false.

1:56:45 So technically I'm putting a true or false value in there.

1:56:49 I'm just getting that true or false value by using a comparison.

1:56:54 And you'll notice over here we're using something called a comparison operator.

1:56:58 And basically this is just like how we want to compare them.

1:57:02 So we're saying like greater than or equal to in this case.

1:57:05 So down here, if this whole condition is true, in other words,

1:57:09 if the results of these two comparisons end up being true,

1:57:13 then we know that num one is the biggest.

1:57:16 So I can just return num one, I can say return num one.

1:57:20 But we also want to check some other conditions.

1:57:23 So I can say L if, and now I want to do some other comparison.

1:57:28 So I'm going to say else if num two is greater than or equal to num one.

1:57:34 And num two is greater than or equal to num three.

1:57:38 So I'm doing essentially what I did up here, except for num two.

1:57:42 So again, I'm comparing these different numbers.

1:57:44 And this is going to end up being a true or a false value,

1:57:48 depending on the result of the comparison.

1:57:51 So down here, again, we can just return num two, because if all of this is true,

1:57:57 that means we're going to end up returning num two.

1:58:00 And then finally, we can just say else.

1:58:03 So if num one isn't the biggest and num two isn't the biggest,

1:58:07 then we can pretty much assume that num three is the biggest.

1:58:12 So now we have our function.

1:58:15 So down here, I'm actually just going to call this function.

1:58:18 So I'm just going to say, actually, I'll print out the result.

1:58:21 So I'll say max num, and we'll pass in like three, four, five.

1:58:27 So we're basically calling that new function that we just made.

1:58:31 And I'm going to go ahead and run this program.

1:58:35 So you can see down here in the output,

1:58:37 we print it out five, because that was the biggest.

1:58:40 If I was to change this middle one to the biggest,

1:58:42 so we make the middle 140, now it'll be able to take on that situation.

1:58:46 And finally, I can make this like 300.

1:58:49 And it'll be able to handle that.

1:58:51 So no matter which number num one num

1:58:53 two or num three ends up being the biggest,

1:58:56 it's able to tell us without a problem.

1:58:59 So these comparisons are a really, really,

1:59:02 really common way to make if statements.

1:59:04 And a lot of times, you're going to want

1:59:07 to be comparing different values inside of Python.

1:59:10 So over here, we're comparing numbers, but we could also compare strings.

1:59:14 So I could easily make these both like, you know,

1:59:17 I could make this like dog, and I can make this dog.

1:59:21 And I could say a different operator.

1:59:23 So I could say like this double equal sign would mean equal.

1:59:27 So I could basically say like, if this string is equal to that string,

1:59:31 so you can basically like compare all different data types,

1:59:35 you know, I could compare numbers, strings, you could also compare bullions.

1:59:40 So once again, these are comparison operators.

1:59:42 And this one is greater than or equal to, but there's

1:59:46 a bunch of other comparison operators we can use.

1:59:48 So the most basic is just going to be a double equal sign.

1:59:52 And that basically checks to see if the two values are equal.

1:59:55 So it'll say like, if number one is equal to number two,

2:00:00 we can also say not equals.

2:00:02 And this and this exclamation point will basically mean not equal.

2:00:07 So it's if num one is not equal to num two,

2:00:12 we also have greater than less than greater

2:00:15 than or equal to less than or equal to.

2:00:18 And those are kind of all of the operators are all the, you know,

2:00:22 the basic comparison operators that you're going to be using in Python.

2:00:26 So using comparisons is really awesome.

2:00:28 And there's going to be tons and tons of situations inside

2:00:31 of Python where you're going to want to compare different values.

2:00:35 So these can be extremely useful.

2:00:38 In this tutorial, I'm going to talk

2:00:41 to you guys about building a calculator in Python.

2:00:44 Now, if you've been following along with this course,

2:00:46 you'll know that in the beginning of the course,

2:00:48 we actually created a very basic calculator.

2:00:51 Basically, the user could just enter in two numbers and our calculator

2:00:55 would add the numbers together and spit out the answer.

2:00:59 In this tutorial, I want to show you

2:01:01 guys how to build a more advanced calculator.

2:01:04 So this calculator is going to be able

2:01:06 to perform all of the basic arithmetic operations.

2:01:08 So we can add, subtract, multiply and divide.

2:01:11 And we'll actually allow the user to specify which one of those they want to do.

2:01:16 So the user will enter in a number,

2:01:18 they'll enter in whatever operator they want to use.

2:01:21 So plus minus divide, multiply.

2:01:23 And then they'll enter in the second

2:01:25 number and we'll perform the operation for them.

2:01:27 So this can be pretty cool.

2:01:29 And it's going to show you how we

2:01:31 can use if statements in like a practical application.

2:01:34 So let's get started.

2:01:36 The first thing we want to do is get input from the user.

2:01:39 So I'm going to create three variables, one for the first number,

2:01:43 one for the second number, and one for the operator.

2:01:46 And we'll basically store the values that the user inputs into those variables.

2:01:50 So the first one will just be num one.

2:01:53 And I'm going to set this equal to input.

2:01:56 And we're going to give this a prompt.

2:01:59 So I'll say enter first number.

2:02:01 And here's actually the thing is whatever the user enters,

2:02:05 we're going to want to convert it into a number.

2:02:09 So generally in Python, when we get input from the user,

2:02:12 no matter what they put in, it just gets converted into a string.

2:02:16 But we don't want a string, because we're going to have to be

2:02:19 adding or subtracting or multiplying these numbers together.

2:02:22 So whenever they enter in the number,

2:02:25 I just want to immediately convert it to an actual

2:02:28 like number data type instead of a string.

2:02:30 So what I can do is I can actually say float,

2:02:34 and I can surround this entire input tag with parentheses.

2:02:37 And now what this is going to do is it's

2:02:41 going to immediately convert whatever the user inputs into a float.

2:02:45 Now that's going to mean that they're going to have to insert a number,

2:02:49 otherwise we'll get an error.

2:02:50 But for the most part, this should work out for us.

2:02:53 So I'm actually just going to copy this guy.

2:02:56 And we'll go ahead and paste it over here.

2:02:59 And we'll paste it one more time.

2:03:01 So we're basically just trying to get three pieces of input from the user.

2:03:04 So the second thing we want to get is the operator.

2:03:07 So I'm just going to say op for operator.

2:03:11 And I'll actually get rid of this float,

2:03:14 because we want to keep this as a string.

2:03:17 And I'll just say enter operator.

2:03:19 So that's going to be like plus minus multiplication, whatever.

2:03:23 And then finally down here, we'll get num two.

2:03:27 And again, we're going to want to convert this to a float.

2:03:31 So I'll say enter second number.

2:03:33 So now basically what we're doing is we're getting the first number,

2:03:36 we're getting the operator and we're getting the second number from the user.

2:03:40 So what we need to do now is we need to figure out what is inside of this op.

2:03:46 In other words, we need to figure out what operator the user was trying to do.

2:03:51 So are they trying to do addition or they trying

2:03:54 to do subtraction like we want to figure that out.

2:03:57 So we can use an if statement in order to figure that out.

2:04:01 So I'm going to come down here and I'm

2:04:03 basically just going to create an if statement.

2:04:06 So I'm going to say if, and we want to check a condition.

2:04:09 So I'm basically going to check to see if this operator is equal to a plus sign.

2:04:15 So I can say if op equals plus sign.

2:04:19 And now if the operator is equal to plus sign,

2:04:22 I'm just going to print out num one plus num two.

2:04:26 But let's say that instead of a plus sign they entered in something else.

2:04:30 So we can say out if op is equal to, and now we'll check if it's a minus sign.

2:04:37 And so here we'll just print num one minus num two.

2:04:41 And actually forgot to put a colon here.

2:04:44 So we can just do these for everything.

2:04:48 So now we can say L if op is equal to division and here we'll

2:04:54 just divide the two numbers so I can print out num one divided by num two.

2:05:00 And finally, we'll do the same thing for multiplication.

2:05:04 So I'll say l if op is equal to asterisk.

2:05:08 And we'll just print out num one times num two.

2:05:14 Alright, so basically over here we have every, you know, condition.

2:05:18 But I also want to put in an else statement.

2:05:21 So in the case that the user enters in an operation,

2:05:25 that's not like one of the four that we specified up here,

2:05:28 I just want to throw an error.

2:05:30 So I'm just going to say op or actually we just say else.

2:05:34 And here we'll just print out like invalid operator.

2:05:39 Alright, so this if statement should give us everything we want.

2:05:43 Basically, I'm just checking to see if it's equal to a plus

2:05:47 sign a minus sign a division sign or a multiplication sign.

2:05:50 Depending on which one it's equal to, we'll do a different operation.

2:05:53 So let's go ahead and run this program and see how we do.

2:05:57 So I'm going to run this program and it says enter first number.

2:06:01 Let's enter five, enter an operator.

2:06:03 So why don't we just do addition and enter a second number.

2:06:08 Let's do 23.

2:06:09 So now it prints out the answer 28.

2:06:13 So a calculator actually works.

2:06:15 Let's try another operator just to make sure.

2:06:18 So we'll do six and why don't we multiply it by, I don't know, 5.23.

2:06:24 So now we go off and we do the multiplication and looks like we got our answer.

2:06:30 So our calculator seems to be working.

2:06:32 And so basically all we did was we got the input from the user

2:06:36 and then we used if statements to figure out what they wanted to do.

2:06:41 So we can check to see if they wanted addition.

2:06:43 We can check to see if they wanted subtraction or division or multiplication.

2:06:46 And we can also check to see if they entered in an invalid operator.

2:06:50 So actually why don't we try that too.

2:06:53 So I'll enter in like five and now we'll just

2:06:57 enter in like an open and close parentheses and a four.

2:07:01 So you can see here it's able to tell like

2:07:04 the program's smart enough to know that that's not a valid operator.

2:07:07 So these if statements can be really powerful and we can use

2:07:10 them in combination with getting the user input to create a little calculator.

2:07:18 In this tutorial I want to talk to you guys about using dictionaries in Python.

2:07:24 Now a dictionary is a special structure in Python which allows

2:07:28 us to store information in what are called key value pairs.

2:07:32 So essentially I can just create a bunch

2:07:35 of these different key value pairs and then when I want

2:07:39 to access a specific piece of information inside of the dictionary

2:07:43 I can just refer to it by its key.

2:07:46 So the word dictionary is actually pretty appropriate here.

2:07:49 If you guys are familiar with a normal dictionary you know in a normal

2:07:53 dictionary you'd have a word and then

2:07:55 you'd have a definition associated to that word.

2:07:58 So in this situation the word would be the key.

2:08:01 In other words the word is what like uniquely identifies it inside

2:08:05 of the dictionary and then the value would be the actual definition.

2:08:10 So this is going to make more sense once we start working

2:08:13 with this but I just wanted to give you guys a quick introduction.

2:08:16 So in this tutorial I want to create a little program that will

2:08:20 allow us to convert a three digit month name into the full month name.

2:08:26 So I could convert for example like JAN to January

2:08:31 or I could convert M A R into March.

2:08:36 Like I want to be able to have a program that can do

2:08:39 that for us and that's actually a pretty good use case for a dictionary.

2:08:43 So we're actually going to create a dictionary and I'm

2:08:45 going to show you guys how we can do that.

2:08:48 So the first thing we need to do

2:08:50 in creating a dictionary is just give it a name.

2:08:52 So I want to give this a specific name.

2:08:55 So I'm just going to call this month conversions.

2:08:58 And now I just want to set this equal to an open and closed curly bracket.

2:09:04 So whenever we create a dictionary in Python we're always going

2:09:07 to want to create it inside of these open and closed curly brackets.

2:09:12 So inside of the dictionary now we can

2:09:15 start defining what are called key value pairs.

2:09:18 So I can define a key and then I can give it a corresponding value.

2:09:23 And the way that we can do that is just

2:09:25 by typing out the key and then typing out the value.

2:09:27 So in our case we're converting three

2:09:29 digit month names into the full month names.

2:09:32 So I would want to type out for example JAN and then I can type a colon

2:09:38 and I want to type out the value I

2:09:40 want to associate with it so we could say January.

2:09:43 I can basically do this for every combination.

2:09:46 So I could say like FEB and this would be February.

2:09:50 And actually after each one of these we're going to need to put a comma.

2:09:55 So I could do the same for March, say M.A.R.

2:10:01 So essentially what I can do is I can specify

2:10:05 an entry inside of this dictionary for each one of these.

2:10:09 So this over here would be the key and this over here would be the value.

2:10:14 And here's one thing is all of these keys have to be unique.

2:10:18 So if I was to come down here and change this to JAN,

2:10:22 this is actually going to give us a little warning.

2:10:24 So you can see down here it says dictionary contains duplicate keys.

2:10:29 That's a no no when we're creating dictionaries.

2:10:31 So you always want to make sure that the keys are unique.

2:10:34 All right.

2:10:34 So I'm going to go ahead and create one of these for each

2:10:38 one of the months and then we'll come back and we'll talk about it.

2:10:41 All right.

2:10:41 So I've gone ahead and created an entry for all 12 of the months.

2:10:46 So now we have a bunch of unique keys and each

2:10:49 one of those keys is associated with a different value.

2:10:52 So this is the basics of creating a dictionary is

2:10:56 we have a bunch of these different key value pairs.

2:10:59 And now what we can actually do is

2:11:01 we can access them from inside of this dictionary.

2:11:04 So if I wanted to access a specific key or a specific value,

2:11:09 all I have to do is come over here and I'm actually just

2:11:12 going to print it out onto the screen so we can see it.

2:11:15 All I have to do is refer to the dictionary by name.

2:11:19 So it's just called month conversions.

2:11:21 And there's actually a bunch of different

2:11:24 ways that I can access these month names.

2:11:27 So I could access different entries inside of this dictionary.

2:11:31 The first way is just by making a open and close square bracket and inside here,

2:11:37 I can just type in one of the keys.

2:11:40 So for example, inside here, I could type in NOV.

2:11:43 And what this should do is it should give us back the full name for November.

2:11:47 So when I print this out, you'll see that we get back down here November.

2:11:52 So I could do the same thing for, you know,

2:11:56 any of these, we could say like M A R.

2:11:58 And now we should get March back.

2:12:00 So I'm able to refer to the key.

2:12:03 And it's going to go into the dictionary and it's

2:12:06 going to give me the value that's associated to that key.

2:12:09 There's actually another way we could do this too.

2:12:12 So I could say month conversions dot get an inside of here.

2:12:16 I could also pass in the name of a key.

2:12:19 So I could pass in like D E C.

2:12:22 And now we'll be printing out December.

2:12:25 And what's cool about using this get function is I can actually specify

2:12:30 a default value that I want to use if this key is not found.

2:12:35 So there's going to be certain cases

2:12:37 when we're dealing with dictionaries where you're going

2:12:39 to put in a key that might not

2:12:41 necessarily map to a value inside of the dictionary.

2:12:44 So you put in an invalid key.

2:12:47 So let's just try to do that.

2:12:49 So I'll just put like L U V.

2:12:51 That's not a month abbreviation.

2:12:52 So when I try to run this, you'll see we get this none down here.

2:12:58 And in a lot of cases,

2:13:00 you're going to want to create some sort of a default value.

2:13:03 So if I'm in this situation where I have a key

2:13:06 that's not mapable to any values inside of this dictionary,

2:13:10 I can actually pass it a default value.

2:13:13 So inside this dot get function, I can make a comma.

2:13:17 And now I can pass in like a default value to get printed out.

2:13:21 So I can say like not a valid key.

2:13:24 And now when I put in the invalid key, instead of saying none,

2:13:27 it's going to go ahead and say not a valid key.

2:13:31 So this is going to give us like a default value that we can fall back on.

2:13:36 So these dictionaries are really awesome.

2:13:38 And the keys over here don't have to be string.

2:13:42 So you could also use numbers.

2:13:43 So for example, I could say like zero, one, 10,

2:13:46 like I can put any numbers I want over here as keys as long as they're unique.

2:13:53 And then I could access those keys,

2:13:55 just like I normally would down here with this get

2:13:58 function or with those open and close square brackets.

2:14:01 So that's sort of the basics of using dictionaries.

2:14:03 It can be really useful to store key value pairs.

2:14:06 And honestly, you're going to be using them

2:14:08 a lot in Python to store different types of data.

2:14:12 In this tutorial, I want to talk to you guys about while loops in Python.

2:14:19 Now a while loop is basically a structure in Python,

2:14:23 which allows us to loop through and execute a block of code multiple times.

2:14:30 So I can specify like a few different lines of code,

2:14:33 and then I can put that code inside of a while loop.

2:14:37 And it would basically loop through that code,

2:14:40 executing it repeatedly until a certain condition was false.

2:14:43 So while loops can be awesome.

2:14:45 And there's a lot of situations in Python where we're

2:14:48 going to want to loop through specific lines of code.

2:14:51 So in this tutorial,

2:14:51 I just want to show you guys the like bare basics of how while loops work.

2:14:55 And then in future tutorials,

2:14:57 we're going to use while loops to create little games and stuff like that.

2:15:01 So let's talk about while loops.

2:15:03 When I create my while loop,

2:15:05 the first thing I want to do actually is create an integer.

2:15:09 I'm basically creating a variable that's a number and you

2:15:12 don't have to do this for a while loop,

2:15:15 but just for our demonstration I'm going to.

2:15:17 So I'm just going to call this I and I'm going to set it equal to one.

2:15:21 And now what I want to do is I want to create a while loop.

2:15:24 So I'm basically just going to say while.

2:15:26 And over here I want to specify a condition.

2:15:31 And this is what's called our loop condition or you

2:15:35 can also refer to it as a loop guard.

2:15:38 And basically we are going to keep looping through the code

2:15:41 inside of the while loop as long as this condition is true.

2:15:45 So whatever condition I put in here, as long as it's true,

2:15:49 we're going to keep looping through the code inside the while loop.

2:15:52 So I'm just going to say while I is less than or equal to 10.

2:15:57 And now I'm going to put a colon and I'm going to make a new line.

2:16:03 And so anything that's below this while loop declaration and that's indented

2:16:08 like this is going to be considered code that's inside the while loop.

2:16:13 And so that code is going to get

2:16:16 repeatedly executed while this condition up here is true.

2:16:19 So I'm just going to put a very simple line of code here.

2:16:23 We're just going to print out the value of I.

2:16:25 And then down here I'm going to actually increment I so I'm going

2:16:29 to add one to I'm going to say I is equal to I plus one.

2:16:34 So basically I'm taking this I value and I'm adding one to it.

2:16:38 There's actually a shorthand that we can use

2:16:40 in Python to do something like this though I could just say I plus equals one

2:16:45 and that's automatically going to add one to I.

2:16:49 So this is like a little shorthand and you'll

2:16:52 see people in Python using that a lot.

2:16:55 So over here we basically have our while loop.

2:16:58 So I have the outline for a while loop.

2:17:01 So we're defining this variable up here and we're going to keep looping through

2:17:05 the code inside the while loop as long as this condition up here is true.

2:17:11 So if this condition is false for example if I is equal to eleven then

2:17:16 we're not going to loop through this code

2:17:18 anymore and we're just going to move on.

2:17:20 So down here I'm actually just going to print.

2:17:23 Done with loop.

2:17:24 So this will kind of illustrate this for us.

2:17:28 Alright so let's go ahead and run this program.

2:17:30 I'm just going to run it.

2:17:32 And you'll see down here we get some output.

2:17:36 So we're actually going to get numbers printed out one all

2:17:39 the way down through ten and then we're printing out done with loop.

2:17:44 So basically what's happening is we're printing

2:17:47 out every time we go through this loop.

2:17:50 So initially I is equal to one right.

2:17:52 The first thing that Python is going to do when it

2:17:54 gets to this while loop is it's going to check this condition.

2:17:56 So before it does anything else it's going to check this condition and it's

2:18:01 going to say okay is one less than or equal to ten and that's true.

2:18:05 So as long as this guy is true we're going

2:18:08 to go through and loop through all the code inside of here.

2:18:11 So we're going to print out i which has the value

2:18:14 of one and then we're going to add one to i.

2:18:17 So now i is going to go from one to two.

2:18:20 Now what we're going to do is we're going to go all the way back

2:18:24 up here to this while loop declaration

2:18:26 and we're going to check the condition again.

2:18:29 So remember I checked the condition the first time and then I loop through all

2:18:33 the code then I go back up to the top and I check it again.

2:18:37 So I'm going to say okay is i less than or equal to ten.

2:18:41 At this point i is equal to two.

2:18:43 So i is less than or equal to ten.

2:18:45 So now we're going to go through and we'll execute all this code again.

2:18:49 So I'm going to print out i so it's going to be two

2:18:51 and I'm going to add one to i so now we have three.

2:18:55 Then Python is going to go all the way back up

2:18:57 to the top and it's going to check the condition again.

2:19:01 So on every iteration through the loop before Python does

2:19:04 what's inside of this loop it's going to check that condition.

2:19:08 And as long as the condition remains true we're

2:19:11 going to keep executing the code inside the loop.

2:19:14 Eventually though in this program i is going to end up being eleven.

2:19:17 So on the last iteration it's going to end up being eleven.

2:19:21 We're going to come back up here and we're going

2:19:23 to say hmm is eleven less than or equal to ten?

2:19:26 Nope.

2:19:27 And so since it's nope we're going to come down

2:19:30 here and we'll print out this done with loop line.

2:19:32 So that's the basics of how these while loops work.

2:19:35 We're specifying a loop condition as long as that condition

2:19:39 is true we'll keep executing the code inside of the loop.

2:19:42 And after every execution of the loop we're going

2:19:44 to come back up and check the condition again.

2:19:47 So that's how we end up with this printing out down here.

2:19:51 So that's the basics of a while loop.

2:19:54 And we can use these while loops to do all sorts of things.

2:19:59 Like while loops are very very powerful.

2:20:03 In this tutorial I'm going to show you guys

2:20:06 how to build a basic guessing game in Python.

2:20:09 And in this guessing game we're actually going to be using all sorts

2:20:13 of cool programming structures that we've learned

2:20:15 up to this point in the course.

2:20:16 So we're going to be using things like if statements and while loops

2:20:19 and variables and all these cool things in order to build this game.

2:20:23 So the basic idea is we will specify like a secret word.

2:20:27 So we'll have a secret word that we store inside of our program.

2:20:31 And then the user can interact with the program

2:20:34 and try to guess the secret word.

2:20:36 And so what we want to be able to happen is we want the user to be able to keep

2:20:40 guessing what the secret word is and keep typing

2:20:42 in different responses until they get the secret word right.

2:20:46 So that's the basics of what this game is going to be.

2:20:50 And now let's go ahead and create it.

2:20:52 So the first thing we want to do is create a variable to store our secret word.

2:20:57 So I could say secret word and we're just

2:21:01 going to set this equal to a secret word.

2:21:02 So why don't we make it draft.

2:21:04 That's a pretty good secret word.

2:21:05 And now what we want to do is we want

2:21:07 to create a variable that will store the user's response.

2:21:10 So I want a variable that will store like all the guesses that the user makes.

2:21:16 So I'm just going to call this guess.

2:21:18 And I'm just going to set it equal to an empty string right now.

2:21:22 So now we have the secret word and we have a variable to store the user's guess.

2:21:27 And what we need to do is we need to be

2:21:30 able to prompt the user to input the secret word.

2:21:33 But here's the catch.

2:21:34 What we want to happen is we want them to enter the secret word.

2:21:38 And if they don't guess it correctly, we want to prompt them to enter it again.

2:21:43 So we can't just use a single input statement.

2:21:47 We actually have to use something called a while loop.

2:21:50 And we can use a while loop in order to continually

2:21:53 ask the person to guess the word until they guess it correctly.

2:21:58 So let's go ahead and create our while loop.

2:22:01 So I'm going to say while.

2:22:02 And after I say while, I need to specify a looping condition or a looping guard.

2:22:08 Basically, this is something that as long as it's true,

2:22:11 we're going to keep looping through this loop.

2:22:13 So basically, I want to say I want to keep looping

2:22:17 as long as the user's guess is not equal to the secret word.

2:22:22 So as long as they haven't guessed the secret word,

2:22:26 I'm going to keep going through this loop.

2:22:29 And inside of this loop,

2:22:31 what we're going to do is we're going to ask them to input the secret word.

2:22:35 So I can take this guess variable and I can set it equal to input.

2:22:40 And I'm just going to say enter guess.

2:22:44 And so over here, we're basically telling the user to enter in their guess.

2:22:50 I'm storing whatever they enter inside of this guess variable.

2:22:55 And then what's going to happen is we're going to come back up here.

2:22:58 We're going to check to see if the guess is equal to the secret word.

2:23:02 If the guess isn't equal to the secret word, then we're going to do it again.

2:23:06 But if the guess is equal to the secret word,

2:23:08 then we're just going to break out of this loop.