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Welcome back.

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We just learned about module's, but let's say our project is getting even bigger.

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We have this main file.

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We have some utility.

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But let's say that we're now working for Microsoft and we have a new, let's say, shopping functionality,

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an entire, let's say, shopping area where you can buy Microsoft T-shirts.

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Well, we can now create a folder so we can add folders to our project.

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And inside of this folder, let's say we have a new file and we'll call this the shopping.

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So now this shopping cart pie.

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Is a folder in our project, you see that our project is getting bigger and bigger, and let's say that

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here we just have a function called by and we give it an item and let's say here we we have a carte

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variable that.

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Let's say adds, it's not a very sophisticated buying system, but for our example, it should be fine

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and then we just return the cart.

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Now, in here we have this by function and let's say in our main file, so up here we want to also import

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our shopping cart by function.

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How can we do that?

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Well, if we tried to do shopping.

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Cart like this, remember, that's the name.

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You see that I get an underlining says imported but unused.

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OK, so does that mean I can use it?

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Let's see, say, shopping cart.

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And if I click, run.

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Module not found error, no module named shopping cart, you see, what we've created here is what we

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call a package.

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A package is simply a folder, and we learned about module, which is these files, these Python files,

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a package is a level up, a package is a folder containing modules so you can have a package with multiple

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modules inside of them.

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So this shopping cart is a module, but this shopping is a package.

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So the way it works when we import from a package is we say the package name.

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So what's the package name?

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It's shopping, and then we do a dot.

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So dot shopping cart.

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So package name and then the module name.

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Now, if we do this, let's see if this works, let's say I do shopping.

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Doctor shopping cart now.

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If I print this, let's make this a little bit smaller.

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All right, now I have access to the shopping cart module by importing the package shopping, which

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is the folder and then the shopping cart, and you notice once again we have a paid cash that was created.

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So let's see if we can use the buy function, so I'm going to say buy and then item, I'll say I'm buying

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just an apple.

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If I click, run.

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There you go.

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I get my Apple list and I was able to import it from a package.

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Now, here's the thing, I want to try and copy what we've just done into a real life scenario, instead

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of using this website, replug it.

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Let's actually create our own project.

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I'm going to use Peja and I recommend you use pajamas.

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Well, just for these next couple of videos.

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Let's open up Iran and let's just create a new project here.

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Now we can call it whatever we want, so let's just call it module's for now for our project, he can

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see where it's being saved.

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And remember, here we get to pick what interpreter we want.

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We're going to talk about this virtual env later on in the videos.

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But the key thing is to make sure that our base interpreter is using Python three, in my case, the

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Python three that we've downloaded and use our local bin.

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If you're on a Mac or Linux, if you're on Windows, this path will probably be different.

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Now we can just create a project.

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And we see here we have our module's.

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Project now we're going to ignore all these folders for now, we're going to talk about them later on.

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The key here is that we want to create a new file.

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I'm going just right click here.

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And we can just call it, let's say, made dot by.

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And notice here that I created in a folder called V and V.

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We'll get back to that shortly.

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Now, let's make this a little bit bigger so we can see and we're going to copy whatever we've just

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done here.

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So I'm going to copy.

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The main file like this that did not copy.

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Let's try that again.

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Like that, and then we're also going to create a few more files, so we'll create a folder.

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So in here, I'm just going to say, right click say new.

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And right away, you see that it python package, I'm going to click on Python package or I can create

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a director if I want as well.

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And when I click here, let's name the package like we've done here as shopping.

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All right, we get our shopping folder.

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And in here, let's right click, say, new new file, and we will call this the shopping cart, DCPI

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So shopping.

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Cart that by.

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And then finally, we'll add our utility file.

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I know we're doing a lot, but, hey, I'm trying to prove a point here.

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Trust me, this is going to be important.

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So utility pie.

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There we go.

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So we have the same setup that we have here.

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Let me copy this over as well.

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All right, and we copy.

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Let's make this bigger like that.

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All right, so we have our files just like we have in our Reppel, except this time we're actually using

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an ID.

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Now, the reason I wanted to transfer over to the ID is that there's an extra file here that we didn't

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see in the Reppel.

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And the Reppel actually hides this away from us.

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You see this underscore in it DCPI file and it's completely empty.

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There's nothing in here.

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One of the rules of a package of a Python package is that on the root of this package, you have to

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have an underscore, underscore in it, underscore, underscore DCPI.

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Now, why is that?

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Well, because the interpreter is going to read this and say, oh, this is a python package.

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Remember how when I right.

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Click here, I said new and then I had an option of a directory or a python package by clicking Python

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package, it automatically added this in it for us.

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So although here everything worked without a net, this is just something that Reppel hides underneath

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the hood.

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Any time you want to create a package, you'll see that we need to have an init file and it can just

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be completely empty.

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Now, the beauty here with pie charts is that it does it for you, which is really, really nice.

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OK, so let's run this code and make sure that it still works.

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So this is our main pie.

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I can simply run the code here by going to run and then selecting run.

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Let's run our main file.

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And we get in there, let's zoom in here.

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And we see that model shopping, the shopping cart has no attribute buy, and that is because we did

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not import the buy function here.

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So let's do that.

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Let's go to shopping cart by.

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Make sure I copy that.

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Paste it in.

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Let's zoom that in and by the way, I'm zooming here on my touchpad.

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I can just use two fingers to zoom in here.

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If I click run again, and this time once you ran it once, you can just click on Run Again.

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And there we have it, we have Apple right here as the output and it says process finished with zip

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code zero in programming.

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When something exits with code zero, it means there were no errors.

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If you get one, well, that's usually an error.

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All right, so we have everything working and this is now are set up, we have our main file, we have

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our other modules like utility, and then we also have our packages and their packages because they

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have this added file and we have different modules in them.

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And as projects get bigger and bigger and we use IDs like petroleum, we organize our functionality,

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our grouping into these packages and modules and really, really good developers are able to organize

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code in really nice packages.

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That makes sense.

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Really nice modules that make sense.

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This is a skill that is really hard to teach.

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It just comes with practice by looking at other people's projects, by working on projects.

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But the key thing is that you want to do what makes sense.

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And when we start working on some of our final projects, we have over 10 projects coming up that we're

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going to work on.

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Now with those ones, you're going to start to learn different ways to organize code as you follow along.

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So don't worry.

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Let's take a break and explore module's a little bit more in the next video.