Some frameworks create implicit URL mappings.

You make a function in a certain file, you can get to that function through a URL

that's usually made up of the file name followed by the function name.

Some frameworks let you assign a route or

URL to a view when you create the function.

Django doesn't do either of these things though.

Django's URLs are created with regular expressions and

have a lot of hidden power in them.

We'll cover some of that power in this course.

For now though, let's just get a single, simple URL created.

If you got really nervous when I said regular expressions, don't worry.

Our first one's going to be super simple,and I'll link to my course on

Python regular expressions in the teacher's notes.

You probably guessed this by now, but the place to go add URLs is the in

the urls.py file in our learning_site stub.

So let's open it up and take a look at it.

Right now it has some comments at the top, and some imports.

And then there is this urlpatterns thing.

Okay, so the first thing we need to do is let's import our views.

We're gonna say from ., which means the current directory.

Import views, and it's funny,

our editor always highlights this as red like it's bad or something.

It's perfectly valid so, just a little strange.

Okay, so we can see that we have this urlpatterns, and

there's already this thing in here.

That's called a URL.

So we're gonna add a new one, all right?

And we'll put it at the bottom, cuz it's like our last thing.

If everything else fails, go to this one, right?

It's not guaranteeing that this is gonna go to this one, but just, that's the idea.

Okay, so we're gonna mark it as a raw string, cuz it's a regex.

And if we do ^$, that makes it an empty string,

cuz that's what we want.

And then we're gonna do views.hello_world,

because hello_world is what we named our view, right?

We come over here and look, hello_world, hello_world.

So, we've imported our views.

We do that so that we have access to our view functions that we've written.

And now we've added a new URL.

So now the URL objects, this thing here, actually takes five different arguments.

The first argument's the pattern, which we've given it, and

that's a regular expression.

In this case we're matching an empty string.

Starts and ends without any characters in the middle.

Any request that comes in to just your site,

with no extra path, is gonna match this pattern.

It's gonna go straight there.

Second part is the view to send the request to, or

the function, rather, to send the request to.

We want to go to the hello_world view,

the hello_world function that we created in the last video.

And we don't wanna use any parentheses here.

We're not calling the view, we just want to go to it,

we wanna know which one it is.

And the remaining parts that we're not using are keyword arguments for

the view, a name for the route, which we'll get to that later, and a prefix.

We don't need to talk about most of those,

we're only gonna talk about the name later.

Okay, so now we have a URL, we have a view.

Let's check out our homepage.

There's our Hello World.

See, that wasn't so bad, was it?

Django URLs are a great way to get more comfortable with regular expressions.

And like I said,

there's a whole other course you can take that's just about regular expressions.

Okay, I think we're ready to create our first app.