栈（Stack）是一种运算受限的线性表。
按照先进后出(FILO，First In Last Out)的原则存储数据，先进入的数据被压入栈底，最后的数据在栈顶。栈只能在一端进行插入和删除操作。
文章内容包含：
（1）栈的基本格式
（2）压栈 push_stack
（3）出栈 pop_stack
（4）取栈顶 peek_stack
class Stack():
def __init__ (self,size):
self.size = size #栈空间大小
self.top = -1 #栈中进入一个数据 top 加 1
self.stack = []
def display_stack(self):#栈stack的打印
print(self.stack)
if __name__ == "__main__":
stack = Stack(5) #设定栈空间
stack.display_stack() #打印栈数据
class Stack():
def __init__ (self,size):
self.size = size
self.top = -1
self.stack = [] #进栈数据列表
def display_stack(self):
print(self.stack)
def push_stack(self,data):
if len(self.stack ) >= self.size: #当数据数量大于设置的空间，则栈溢出
print("stack over flow!")
return
self.stack.append(data) #没有栈溢出就将数据追加到列表中
self.top += 1 #栈中每增加一个数据就加 1
if __name__ == "__main__":
stack = Stack(5)
stack.push_stack(0)
stack.push_stack(1)
stack.push_stack(2)
stack.push_stack(3)
stack.push_stack(4)
stack.push_stack(5) #stack空间是 5，这里进栈数据时 6 个，即提示栈溢出stack over flow！
stack.display_stack()
执行结果：
class Stack():
def __init__ (self,size):
self.size = size
self.top = -1
self.stack = [] #进栈数据列表
def display_stack(self):
print(self.stack)
def push_stack(self,data):
if len(self.stack ) >= self.size:
print("stack over flow!")
return
self.stack.append(data)
self.top += 1
def pop_stack(self):
if self.top <= -1: #当top小于等于初始值 -1 时说明stack数据列表为空
print("stack is empty!")
return
ret = self.stack.pop() #stack数据列表不为空就取出最后进的值，列表数据数量就少一个
self.top -= 1
return ret
if __name__ == "__main__":
stack = Stack(5)
stack.push_stack(0)
stack.push_stack(1)
stack.push_stack(2)
stack.push_stack(3)
stack.push_stack(4)
stack.display_stack()
#进栈数据有 5 个，出栈函数调用了 6 次，就出现了提示stack is empty!
ret = stack.pop_stack()
print(ret)
stack.display_stack()
ret = stack.pop_stack()
print(ret)
stack.display_stack()
ret = stack.pop_stack()
print(ret)
stack.display_stack()
ret = stack.pop_stack()
print(ret)
stack.display_stack()
ret = stack.pop_stack()
print(ret)
stack.display_stack()
ret = stack.pop_stack()
print(ret)
stack.display_stack()
执行结果：
class Stack():
def __init__ (self,size):
self.size = size
self.top = -1
self.stack = []
def display_stack(self):
print(self.stack)
def push_stack(self,data):
if len(self.stack ) >= self.size:
print("stack over flow!")
return
self.stack.append(data)
self.top += 1
def peek_stack(self):
if self.top == -1: #当栈内没有数据时 提示 stack is empty!
print("stack is empty!")
return
peek = self.stack[self.top] #栈不为空时，将栈顶的数据提取出来
return peek
if __name__ == "__main__":
stack = Stack(5)
stack.push_stack(0)
stack.push_stack(1)
stack.push_stack(2)
stack.push_stack(3)
stack.push_stack(4)
stack.push_stack(5)
stack.display_stack()
peek = stack.peek_stack()
print(peek)
执行结果：
