栈

先进后出

pyhton 3.x写不写object都可以， class stack(object):
默认写了object，拥有好多操作对象

以前不写object的话，就只有几个默认的操作对象

 1 class Stack():
 2     def __init__(self,mystack=[]):
 3         self._stack = mystack
 4     def push(self,data):
 5         self._stack.append(data)
 6     def pop(self):
 7         self._stack.pop()
 8     def is_empty(self):
 9         return len(self._stack) == 0
10     def peek(self):
11         return self._stack[-1]
12     def size(self):
13         return len(self._stack)
14     def print1(self):
15         print(self._stack)
16 myStack = Stack()
17 print('原栈：',end='')
18 myStack.print1()
19 
20 print('压栈：')
21 for i in range(5):
22     myStack.push(i)
23     myStack.print1()
24 print('出栈:')
25 for j in range(5):
26     myStack.pop()
27     myStack.print1()