Original subtitles

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In previous lessons,

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I've already mentioned how important it is in Python to be aware of your

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indentation. So we know that when we create a function like this,

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that every line that comes after this definition

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that is indented is going to be inside this function.

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So by indented, I mean

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it's shifted to the right by four spaces like this.

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So if you imagine each dot as a space, then this is a single block of code.

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And if we want to continue adding to this block of code inside my function,

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then we would continue adding lines of code, which are indented.

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So you have to almost visualize for yourself this invisible line around these

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blocks of code, which are indented. Now,

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if my code was written like this on the other hand,

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then the block of code is in fact only this part. And this print statement will

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not get triggered when this function gets triggered because it's independent

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from this function because it's not indented. Now, a simple way

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that I like to think about this kind of indentation is kind of like the file

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structure you see when you go into finder on the Mac,

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or when you go into Explorer on Windows.

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If we have a function,

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it's kind of like a folder and anything that goes inside the function,

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for example, if I throw this file inside the function,

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then you notice that it gets indented, right?

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And this way it shows to you very,

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very clearly that these two files print-

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hello and print-world are living inside this folder,

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my function. And this is the equivalent of this code.

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We have this folder say, my_function, and it contains these two lines of code.

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Now, on the other hand,

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if I take this print world and I put it outside of the function folder,

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then you can see that this is completely independent from that folder.

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And it's now indented at the same level as the function.

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So this is the equivalent of this code, where we've got this print-

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hello being inside the

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my_function and this print-world being outside and at the same indentation level

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as this function definition. Now,

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the indentation gets a little bit more complicated when we have other blocks of

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code. So for example, the, if/elif/else statements.

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They have blocks of code,

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which need to be indented to be inside the block.

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For loops need to be indented to be inside the loop.

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And it's very important that you get used to looking at blocks of code like

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this. So for example, if we were to expand our simple

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my_function and add a whole bunch of code into it,

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then we would have to indent all of those lines of code by four spaces

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represented by the four dots here. Now, if we wanted to have

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another block of code inside this if statement,

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then this line has to be indented,

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a further four spaces.

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So this is the function block,

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this is the if block,

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this is the elif block and you have to be able to see all of this while just

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looking at the indentation. If we wanted to represent this,

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then it's almost like creating a new folder. Let's call it the

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If sky == clear.

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And this if block goes inside my function, so it's indented.

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Now, if I wanted to have a print statement,

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let's call it print-blue inside this if statement.

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So this is what should be executed if this function gets called

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and if the sky is equal to clear, well

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then this line is indented twice.

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And that is the equivalent of four spaces in our code, like this.

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Now, every time I've talked about indentation,

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I've been talking about spaces and actually there's two ways of creating

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indentation. You don't have to just use spaces.

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You can also use tabs and that's created using the tab key on your keyboard,

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which can look a little bit like this.

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Now there's a lot of debate around spaces and tabs where some people prefer

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using spaces to indent, other people prefer tabs to indent.

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And there's a lot of people arguing in the coding community.

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And I think this excerpt from one of my favorite shows really demonstrates this.

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Richard what's wrong? Nothing, nothing, literally. It's all good.

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Come on. Oh my God. Your roommates are right. You really hate spaces.

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No, no, no, no. I don't. It's not hate, hate is a strong word. Um,

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truth be told I do have a slight preference for tabs,

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but that's only because I'm anal

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and because I prefer precision.

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Well, not to pick a fight here,

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but if you really care about precision why don't you use spaces?

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But whatever, once it goes through the compiler, it's the same thing, right?

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Yeah. Yeah. Technically, yes.

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Right.

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I guess I just, I just don't understand why anyone would use spaces over tabs.

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Like if it's all the same,

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why not just use tabs? Because it could look different on other people's

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computers. Tabs create smaller file sizes. All right.

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I run a compression company. Trust me.

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I've devoted my life to minimalizing file sizes. It's what I do. I mean,

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I do not get why anyone would use spaces over tabs. I mean,

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why not just use VIM over Emacs? I do use VIM over Emacs. Oh, God help us.

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Okay. Uh, you know what? I just, I don't think this is gonna work.

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I'm so sorry. Uh, I mean like what,

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we're going to bring kids into this world with that over the head.

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Stuff's not really fair to them. Don't you think? Kids?

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we haven't even slept together. And guess what?

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It's never going to happen now because there is no way I'm going to be with

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someone who uses spaces over tabs.

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So should you be using spaces or should you be using tabs?

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The age old question and the extent to which people obsess over this question,

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it really shows in this 2017 Stack Overflow developer survey,

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where they are asked the developers, do you use spaces or do you use tabs?

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And then they compare it against their annual salary

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and somehow have managed to show that the people who use spaces seem to earn a

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lot more than the people who use tabs.

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Now the official guide from the Python community is in fact to use spaces.

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So if you click on the section, tabs or spaces,

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they tell you in no uncertain words,

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that spaces are the preferred indentation method.

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And in fact, in Python 3,

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you can't mix a code file that uses tabs and spaces for indentation in the same

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file. And it also tells you that in order to indent a line of code,

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it should be indented using four spaces,

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so four hits of the space bar. Now,

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for a lot of people, that may seem quite inefficient because I have to hit my

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space bar

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four times in order to achieve a single indent.

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And you've seen how much we indent throughout our code. So it seems very,

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very inefficient.

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But luckily in most code editors,

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they actually have a setting that allows you to indent using spaces,

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changing the indent size to four.

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And when you hit the tab key,

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it will automatically insert four spaces,

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which you can tell when you're trying to highlight this space,

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you can see the cursor is jumping four times.

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This means that you get to hit tab once and that your code is in line with the

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guidance because the hind the scenes

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your code editor is inserting four spaces.

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So I hope that clears up a little bit on tabs versus spaces.

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And I highly recommend you to head over to the course resources and click on the link

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to go to the style guide for Python code and take a look through the parts about

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indentation. Now in the next lesson, I've got a quick quiz for you

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to test your knowledge on indentation. So for all of that and more,

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I'll see you on the next lesson.