python has a built-in stack data structure defined under the module stack.py code example

Example 1: def dft(self, array): stack = Stack() visited = set() stack.append(self) while len(stack) > 0 and while len(visited) >= 0: current = stack.pop() array.append(current) visited.add(current) return array

def dft(self, array):
    stack = Stack()
    visited = set()
    stack.append(self)
    while len(stack) > 0 and while len(visited) >= 0:
        current = stack.pop()
        array.append(current)
        visited.add(current)
    return array

Example 2: stack using array python

class ArrayStack:
	def __init__(self):
		self._data = []

	def __len(self):
		return len(self._data)

	def is_empty(self):
		return len(self._data) == 0

	def push(self, e):
		self._data.append(e)

	def pop(self):
		if self.is_empty():
			raise Empty('stack is empty')
		else:
			return self._data.pop()

	def top(self):
		if self.is_empty():
			raise Empty('Stack is empty')
		else:
			return self._data[-1]

	@property
	def data(self):
		return self._data


class Empty(Exception):
	pass

Example 3: stack program in python 3

>>> myStack = []

>>> myStack.append('a')
>>> myStack.append('b')
>>> myStack.append('c')

>>> myStack
['a', 'b', 'c']

>>> myStack.pop()
'c'
>>> myStack.pop()
'b'
>>> myStack.pop()
'a'

>>> myStack.pop()
Traceback (most recent call last):
File "<console>", line 1, in <module>
IndexError: pop from empty list