Name: Pythonで関数を使う方法 (Pythonチュートリアル #3) (How To Use Functions In Python (Python Tutorial #3))
Uploaded: 2021-01-14T10:25:02.000Z
Duration: 14 min 55 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

Oh, it's like it here in this video, I'm gonna cover what functions are on how to use them in python and using a function.

By the end of this video, you'll be able to create a B M I calculator similar to the one we created in the last video.

But you'll be able to use this one repeatedly for many different people and many different variables.

I'm also gonna cover what comments are on how to use them.

And as usual, I'll put the outline of this course below.

So you don't have to watch the whole thing.

Let me first begin by answering a question, though.

Although I downloaded Jupiter on my MacBook, I was unable to open your Jupiter notebook sample files.

So if you download a sample file, for example, from C s no, Joe, that I owe slash python to for the last video.

If you just click the file that you just don't want it, this one on this stop, it actually won't open it.

So what you need to do instead is you need to launch debate a notebook in any way you'd like to launch it.

I'm gonna use Anaconda Navigator here on once you launched jibber notebook within the Jupiter notebook.

You I you need to go to wherever you downloaded the file, for example, desktop and then click the file that you just don't want it within Jupiter notebook.

And that way you'll be able to open the file and they use it on.

Edit it on for this video, you can just go to see a soldier that I owe.

Slash Python three to download the sample files.

With that out of the way, let's dive into our main topic today, which is what our functions.

I created a folder called Python Tutorial three on desktop on a new notebook file called What Are Functions?

So there are actually a few different ways of looking at functions.

One way to look at it is that it's a collection off structures or it's a collection of coat and notice here that these lies I wrote here, they're not pieces of python code.

There's something called comments, so comments are used to comment on the code that we're going to write below so you can use it to.

For example, explain, while viable, is your defining on.

And so and we can tell that these two lines are comments because each of these two lines begin with the pound sign or the hashtag so function can be simply a collection of could.

Let's see an example of that deaf functional one parentheses, colon print.

This whole block says death for define so defined the falling function and then give it a name which we can choose.

We can call it any name we want for some function.

Let's keep it at function one for now on them parentheses.

Four spaces print are on four spaces again.

Ah, too of these spaces in front of these two lines are really important, just like with if l statements to show that these two lines are part of this function.

If you have, for example, four spaces here on five spaces or three spaces it just wouldn't work on.

As you can see, outside of this function, we have a print statement that Prince, this is outside the function.

Let's see what happens once we load or run this cell.

As you can see on Lee, this line has been printed.

What happened was dysfunction called functional.

One has been defined as a collection of code.

These two lines of code prints are on print are too.

And after that, son, this line has been executed.

So these two lines of code prints are on print.

Are too will not be executed, will not be run until we use dysfunction.

Or we call, as we say, dysfunction, to use dysfunction or to call dysfunction.

You can just write function one open parent disease, close parentheses and that's it.

When you run this cell, what's gonna happen is these two lines of code will be executed for the first time.

And the nice thing about functions is that you can reuse them over and over again so you can write functional one over here again, and actually, you can even use it twice in the same cell.

And so when you run this cell function, one is executed twice, and these two lines of code are executed twice as well.

Okay, in addition to being a collection off instructions or a collection of code, a function can also be a mapping.

So let's take a look at an example of that deaf function to parentheses.

X colon return two times X or two star ex.

This means define a function called function to which is going to take the input or an argument on that argument.

And in return to whoever called dysfunction, we're going to return two times X.

So we're mapping the input X to the up, put two times X, execute this cell and to use dysfunction or to call dysfunction, you can write a eco's function, too.

And this is as an argument used three on call dysfunction function, too, And once this expression is evaluated, function to fantasise, three will return two Times X in this case two times three, which is six.

And then that number six will be assigned to the viable eh?

And that number six is called a return value or output.

Let's see if this expression works by running to sell on by printing A and we should say six and we do.

Okay, let's try using this function a few more times.

If you write be Eco's function to parentheses for function to of parenthesis.

So once we print be, we should see eight and we do on.

If you write Sea Eagles function to our five on every print.

And what if you try to call dysfunction without any arguments?

So if you're right, D goes function to parentheses with nothing inside, let's try running it.

It will actually give us an error saying function to missing one record Positional argument.

So this was an example off a function that maps one argument to a return value.

Is it possible to have multiple arguments in a single function?

For that you can write deaf function three X comma space.

Why Colon and then let's write Return X plus Why this means Let's define a function called function three.

And then this function is going to take two arguments X and Y on Return X plus y.

Let's load this function by running the cell on Let's write e Eco's function.

So function 31 comma space to should be evaluated to one plus two, which is three.

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Pythonで関数を使う方法 (Pythonチュートリアル #3) (How To Use Functions In Python (Python Tutorial #3))

expression

determine

hypothetical

assumption