The pop() method removes and returns the topmost item of the stack. In this video, learn how to use the Python list's built-in pop() method to implement this behavior.
- [Instructor] The second method we can work on…is our Pop Method.…And this is the method that's going to allow us…to remove an item from the top of the stack.…Now, we know already that the list data type…has a built in Pop Method.…So, we're just going to make use of that.…So, we will return whatever value…is given to us by self.items.pop.…Now, we don't have to specify an index here,…because we always are going to be wanting it…to return us the last item from the list.…
That's how the Pop Method works.…If you don't give it any parameters,…it will always return the last method.…That's pretty much it.…Let's add another doc string, as we did for Push.…So, what does this method do?…This method…returns the last item.…We should say, removes and returns the last item…from the list,…which is also…the top item of the stack.…
And just as we did before, we should talk about…the run time here, as well.…And the run time is also constant time,…just as it was for Push.…Because really, all we're doing is, we are indexing…to that last item in the list and then returning it.…
Author
Released
12/6/2018- Abstract types and data structures
- Stacks as a linear abstract data type
- Creating the Stack class and its methods
- Adding items to the top and bottom of a stack
- Creating the Queue class and its methods
- Manipulating items in a queue
- Creating the Dequeue class and its methods
- Adding and removing items from a dequeue
Skill Level Advanced
Duration
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Introduction
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What you should know1m 26s
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1. Abstract Data Types and Data Structures
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Abstract data types3m 28s
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Data structures40s
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2. The Stack
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push()3m 27s
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pop()3m 57s
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peek()3m 28s
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size()1m 51s
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is_empty()2m 13s
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Challenge: Balanced symbols1m 10s
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3. The Queue
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enqueue()3m 8s
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dequeue()3m 29s
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peek()3m 43s
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size() and is_empty()3m 2s
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Challenge: Print queue1m 14s
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Print queue solution in code4m 19s
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4. The Deque
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add_rear() and add_front()4m 21s
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peek_rear() and peek_front()3m 50s
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Conclusion
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Next steps1m 43s
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Video: pop()