Implementing a Stack in Python
Tl;dr #
- Use
.append()andpop()together for traditional stack (most common usage) - Use
insert(0, item)andpop()if you want a LIFO stack
Stack #
Stacks can be implemented using a set() or a list().
Both allow some sort of enque method and a list.pop()/set.pop() as deque methods.
List implementation #
To implement it using a list,
my_stack = []
# Push
my_stack.append('a')
# >> ['a']
my_stack.append('b')
# >> ['a', 'b']
my_stack.append('c')
# >> ['a', 'b', 'c']
# Pop
my_stack.pop()
# Returns 'c' (last item appended)
# my_stack: ['a', 'b']
my_stack.pop()
# Returns 'b' (2nd item appended)
# my_stack: ['a']
my_stack.pop()
# Returns 'a' (1st item appended)
# my_stack: []
The python pop() method on a list, removes the last item of the list and returns it to you.
[1, 2, 3, 4, 5, 6, 7, 8, 9].pop()
# Λ
# _____________|
# |
# 9 is removed and returned
# when you call a pop()!