栈的实现
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class StackOne(object):
"""栈"""
def __init__(self):
self.__items=[]
def is_empty(self):
"""判断是否为空"""
return self.__items == []
def push(self,item):
"""加入元素"""
self.__items.append(item)
def pop(self):
"""弹出元素"""
return self.__items.pop()
def peek(self):
"""返回栈顶元素"""
return self.__items[len(self.__items) - 1]
def size(self):
"""返回栈的大小"""
return len(self.__items)
if __name__ == "__main__":
stack = StackOne()
stack.push("hello")
stack.push("world")
stack.push("itcast")
print(stack.size())
print(stack.peek())
print(stack.pop())
print(stack.pop())
print(stack.pop())