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- [Instructor] We've now looked
at most of the methods of

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the list type in Python,
but there is another method

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that we haven't taken
a look at yet, which is

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the pop method.

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So if you're familiar with
data structures like a stacked

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data structure or a queue data structure,

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a stack is a Last In
First Out data structure.

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A queue is a First In
First Out data structure.

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You can actually implement
those types of data structures

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using the methods that
I've shown you so far

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and the pop method that
I'm about to demonstrate

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for you as well.

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So, if, for example, I were
to create a stack variable,

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which is just an empty list,
I can go ahead and start

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appending items to that list.

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So let's say I append "red".

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Now at this point, "red"
is the top of the stack,

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if we're maintaining the
list as a Last in First Out

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data structure.

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So we can go ahead and see
what the stack contains

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at the moment, and let's add another item.

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So at this point, we'll add
"green", and if we evaluate

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the stack again, "green"
is at the end of the list.

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So, so far we're adding to the end only.

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If we then remove from
the end, that would be

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the top element of the stack,
and the last item I added,

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"green", would be the first item I remove.

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So we can use the pop method that way.

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So popping the stack gives me green.

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Popping the stack gives me "red".

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At this point, the stack
is empty, but if I were to

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try to pop the stack again,
you can see that I get

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an exception in that case.

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An index error indicating
that I tried to pop from

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an empty list, which is
not allowed, and therefore

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you get the exception
in that particular case.

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So, as you saw here, you can
certainly mimic the concept

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of a stacked data structure
and it would be easy to do

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something similar to mimic a
queue data structure as well.