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Stack
A stack is a data structure that stores items in a "last in, first out" (LIFO) manner. New elements are added to and removed from the end of a stack. When an item is added to a stack, the operation is known as a "push". When an item is removed from a stack, the operation is known as a "pop".
A simple stack can easily be implemented in Python using the List built-in data structure.
stack = [] # empty stack using the List structure. stack.append(23) stack.append(98) stack.append(5) element1 = stack.pop() # pops 5 from the stack and sets the value of element1 to 5 element2 = stack.pop() # pops 98 from the stack and sets the value of element2 to 98
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Python Programming Language
Data Science
Computing Sciences
Foundations of Large Language Models Course
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Initial State in Bracket Balancing: Empty Stack
Consider the following sequence of operations on a data structure that behaves in a 'last-in, first-out' manner. What will be the final contents of the
data_structurelist after all the operations are executed?data_structure = [] data_structure.append('A') data_structure.append('B') data_structure.pop() data_structure.append('C') data_structure.append('D') data_structure.pop()Implementing an 'Undo' Feature
Consider the following Python code snippet which uses a list to simulate a data structure that operates on a 'last-in, first-out' (LIFO) principle. Arrange the following states of the
itemslist in the chronological order they occur as the code executes from top to bottom.items = [] items.append(42) # State 1 items.append(15) # State 2 items.pop() # State 3 items.append(88) # State 4