Python-栈

一.

class Stack(object):    """docstring for Stack"""    def __init__(self, size):        self.stack = []        self.size = size        self.top = -1    def push(self,content):        if self.full():            print("stack is full")        else:            self.stack.append(content)            self.top = self.top + 1    def pop(self,content):        if self.empty():            print("stack is empty")        else:            self.top = self.top - 1    def empty(self):        if self.top == -1:            return True        else:            return False    def full(self):        if self.top == self.size:            return True        else:            return Falsestack = Stack(9)# stack.push(3)stack.pop(3)print(stack.empty())

1.首先定义一个Stack类
初始化这个类,定义self.stack为列表,然后我们在给他添加条件,因为列表是任何位置都可以取元素,而栈是FILO结构.

2.判断栈是否空或者满
空的话就是self.top == -1,满的话就是top指针和栈大小相同,即self.top == self.size

def empty(self):def full(self):

3.进栈操作如下

def push(self,content):        if self.full():            print("stack is full")        else:            self.stack.append(content)            self.top = self.top + 1

先判断是否满,如果满就放不下了,不满的话,列表追加一个元素,就是我们传进去的content,然后top指针再加1,再赋给self.top,相当于self.top++
注意Python中没有self.top++这种操作,但可以self.top+=1或者相应的self.top-=1

4.出栈操作如下

def pop(self,content):        if self.empty():            print("stack is empty")        else:            self.top = self.top - 1

self.top减去1,然后再赋给self.top

二.

class Stack():    def __init__(self):        self._elems = []    def is_empty(self):        return self._elems == []    def top(self):        if self._elems == []:            print("Stack is empty")        return -1    def push(self,elem):        self._elems.append(elem)    def pop_(self):        if self._elems == []:            print("Stack is empty")        #删除并返回最后一个元素,即删除的元素        return self._elems.pop()stack = Stack()stack.push(3)stack.push(5)while not stack.is_empty():    print(stack.pop_())