stack.py

#-*-coding:utf-8-*-
class Stack(object):
 def __init__(self, limit=10):
 self.stack = [] #存放元素
 self.limit = limit #栈容量极限
 def push(self, data): #入栈
 if len(self.stack) >= self.limit:
 print('StackOverflowError')
 self.stack.append(data)
 def pop(self):#出栈
 if self.stack:
 return self.stack.pop()
 else:
 raise IndexError('pop from an empty stack') #空栈不能被弹出
 def peek(self): #查看堆栈的最上面的元素
 if self.stack:
 return self.stack[-1]
 def is_empty(self): #判断栈是否为空
 return not bool(self.stack)
 def size(self): #返回栈的大小
 return len(self.stack)
if __name__ =="__main__":
 stack=Stack()
 print(stack.is_empty())#True
 print(stack.size())#0
 stack.push([1])
 stack.push([3])
 stack.push([2])
 print(stack.peek())#[2]
 print(stack.is_empty())#False
 print(stack.size())#3
 print(stack.pop())#[2]
 print(stack.peek())# [3]