stack_01.py

#!/usr/bin/python3
# ==================================================================
# From: www.youtube.com/watch?v=IVFnq4zbs-g
# ==================================================================

"""
Stack Data Structure

push - put an item on the top of the stack
pop  - remove (return) the top item of the stack
"""

class Stack():
    def __init__(self):
        self.items = []

    def push(self,item):
        self.items.append(item)

    def pop(self):
        return self.items.pop()

    def is_empty(self):
        return self.items == []

    def peek(self):
        if not self.is_empty():
            return self.items[-1]
        else:
            return None

    def get_stack(self):
        return self.items

# ---- main --------------------------------------------------------

s = Stack()

print(s.peek())

s.push("A")
s.push("B")

print(s.peek())

print(s.get_stack())                ## display the stack (list)