Heads up! To view this whole video, sign in with your Courses account or enroll in your free 7-day trial. Sign In Enroll
Well done!
You have completed Introducing Lists!
You have completed Introducing Lists!
Preview
Let's wrap up this application and review it in its entirety.
Related Discussions
Have questions about this video? Start a discussion with the community and Treehouse staff.
Sign upRelated Discussions
Have questions about this video? Start a discussion with the community and Treehouse staff.
Sign up
Okay, first thing's first, I'm gonna wipe
our all these instructional columns.
0:00
Let's get rid of all of these,
clean that up a bit.
0:05
Let's get a little noisy.
0:08
All right, awesome.
0:11
So, that feels better.
0:13
Let's look at what we have left.
0:15
All right so we left done here because
we want to print the list out in
0:18
totality when it's done.
0:21
We wanna show the list and
there's this one here too.
0:22
I wanna see the list any time so
I can verify my order.
0:25
So let's make a new command for that.
0:28
That sounds good, all right?
0:31
So let's come back over here.
0:32
So first,
I'm gonna clean this up a little bit.
0:33
I'm gonna move this add to list
down below the show help and
0:36
typically what happens
in between functions,
0:41
you'll see that the starts getting
busy is you leave two spaces.
0:44
So there we, so we left that two
spaces between the two there.
0:48
Before and after, there you go.
0:52
All right, so we want to define a new
function that's named show list.
0:55
So let's do that.
1:03
So we'll say, define a function
1:03
named show_list that prints
1:10
all the items in the list.
1:15
That sounds good, right?
1:21
You got this, right?
1:23
You can loop through all of them and
print them out, right?
1:24
You got this, ready?
1:27
Pause me.
How did it go?
1:28
Here's how I did it.
1:31
So I said def show list.
1:32
Here's your list,
nice little heading there for it.
1:40
And we're gonna loop through that list.
1:45
So for each of the items In the shopping
list, we are going to print said item.
1:48
Awesome, and now,
we want to be able to have this called.
1:56
So let's make the command SHOW,
in all upper case.
2:04
So let's put it right here.
2:08
We'll say Enable the SHOW command,
2:09
cuz we wanna call that function
SHOW command to show the list.
2:16
Don't forget to update
the help documentation.
2:22
This is super important.
2:26
Sometimes you'll add a new command and
2:27
you'll forget that you've
already made this help.
2:29
And we have the help at the top of
the file, so don't forget to do that and
2:31
I wanna drop a hint here for you.
2:35
Make sure to run it.
2:38
Make sure that you run this
after you had that show command.
2:41
There's a little gotcha
if you forget something.
2:44
So make sure you run it, and
just make sure your list looks right.
2:46
Are you ready?
2:50
Pause me.
2:50
Did you catch it?
2:52
Here's what I did.
2:53
So I went ahead and it's another else if.
2:54
And if this is equal to our command
of show, we call the function.
2:57
But we got to remember to
use our control flow, right?
3:05
We gotta call continue and
3:09
if not, what will happen is show
will end up in your grocery list.
3:11
When you embrace flow control
like break and continue,
3:16
it's super important that you pay
attention to all the used cases.
3:18
All right, we are so close to done.
3:21
Now, we need to show
the list on completion.
3:24
So what we can do is when this while
loop is over while this while true when
3:27
this is over.
3:32
We can just call it.
3:34
We will call show_list.
3:38
Awesome let's give that a run.
3:43
Let's say, Python shopping list.
3:45
Look what I forgot to do.
3:55
I didn't update the help,
so I don't know about show.
3:57
I'm gonna do that.
3:59
Let me get back up in there.
4:00
Let's go back up in here.
4:01
So we'll add enter SHOW
4:04
to see your current list.
4:11
Awesome, whew that was close.
4:15
Okay so
we're gonna run Python shopping_list.py.
4:18
There's the show which
we pick up at the store.
4:24
Well obviously we need some tortillas.
4:29
Let's get some green chiles.
4:33
I need pork shoulder.
4:38
What am I forgetting?
4:41
What's on my list again?
4:42
What do I have here?
4:44
Right, tortillas, green chiles,
pork shoulders, cilantro.
4:46
There we go and now I am DONE.
4:52
And check it out there is my final list,
4:54
you're totally invited to my taco fiesta,
look at this.
4:57
We are all done, awesome.
5:01
Should we walk it one more time?
5:06
Let's do that.
So I'm gonna come in here.
5:09
I'm gonna get rid of these instructional
commands that we have in here.
5:10
Let's just walk it.
5:16
So we create our brand new list that
the program will use in a global fashion.
5:18
And then our program is gonna
accept multiple commands.
5:24
So we should have some detailed help,
right?
5:28
Programs are no good if
users can't use them.
5:30
So we print out our help, and
then we have our add to list function.
5:32
And it appends a value to
the end of our shopping list and
5:38
updates the user with the count.
5:41
And lists and most objects for
5:45
that matter can make use of
the len command, so pythonic.
5:46
And then we have our show list,
and lists are iterable,
5:52
so we can loop through them
with a for item in list.
5:57
Now, this is kind of strange, right?
6:01
So we have this while True.
6:05
One way to write loop that take
many flows is to set things up
6:07
in an infinite loop matter.
6:10
While true is always gonna happen,
6:12
we rely on further control flow
to control how things happen.
6:14
We take a single prompt and
since it can be an item or
6:20
a command,
we have made the prompt generic.
6:24
A little greater than sign,
feels kinda good.
6:27
And then we just check
each of our commands.
6:30
So here's the flow if the user is done.
6:33
Break out of the while loop,
we are done with this while loop,
6:38
we don't anything more to do so
break out of it.
6:41
Otherwise if we're looking for help,
show it and remember to control the flow.
6:44
Calling continue will shoot us back up to
this while true line which is no surprise,
6:51
still true.
6:56
What this avoids is us from continuing and
adding help to our grocery list.
6:58
We don't want that.
7:02
Well, at least not from the grocery store.
7:03
Now, I of course, could have just put this
add to list inside of an else and we could
7:05
remove the continues, but then I would've
been able to show you the continue loop.
7:10
So I want you to be cautious of
controlling the flow with break and
7:14
continue.
7:18
Break is known to break your program,
7:19
and then finally we add that
new item to our function.
7:21
It comes into the add to list then boom,
here we go.
7:26
So I hope that that all made sense, and
7:29
if there is anything at all that is still
confusing you, feel free, rewind it,
7:32
watch it again and hit the forum if
there's anything confusing at all.
7:36
You did an awesome job,
enjoy the taco party.
7:40
You need to sign up for Treehouse in order to download course files.
Sign upYou need to sign up for Treehouse in order to set up Workspace
Sign up