介绍

数据结构在计算机中组织存储，以便我们可以有效地访问和更改数据。 堆栈和队列是计算机科学中定义的最早的数据结构。

堆栈

遵循后进先出 (Last-in-First-Out LIFO)原则。

• push - 在堆栈顶部添加元素：

• pop - 删除堆栈顶部的元素：

队列

遵循先入先出(FIFO:First-in-First-Out)原则。

• enqueue - 在队列的开头添加元素：

• dequeue - 删除队列开头的元素：

使用列表实现堆栈和队列

Python的内置List数据结构k堆栈和队列操作的方法。

堆栈

letters = []# Let's push some letters into our listletters.append('c')  letters.append('a')  letters.append('t')  letters.append('g')# Now let's pop letters, we should get 'g'last_item = letters.pop()  print(last_item)# If we pop again we'll get 't'last_item = letters.pop()  print(last_item)# 'c' and 'a' remainprint(letters) # ['c', 'a']

执行结果

gt['c', 'a']

队列

fruits = []# Let's enqueue some fruits into our listfruits.append('banana')  fruits.append('grapes')  fruits.append('mango')  fruits.append('orange')# Now let's dequeue our fruits, we should get 'banana'first_item = fruits.pop(0)  print(first_item)# If we dequeue again we'll get 'grapes'first_item = fruits.pop(0)  print(first_item)# 'mango' and 'orange' remainprint(fruits) # ['c', 'a']

执行结果

bananagrapes['mango', 'orange']

使用Deque库的堆栈和队列

deque是Double Ended Queue的缩写 - 可以获取存储的第一个或最后一个元素的通用队列，下面我们使用Deque库的堆栈和队列：

from collections import deque# you can initialize a deque with a list numbers = deque()# Use append like before to add elementsnumbers.append(99)  numbers.append(15)  numbers.append(82)  numbers.append(50)  numbers.append(47)# You can pop like a stacklast_item = numbers.pop()  print(last_item) # 47  print(numbers) # deque([99, 15, 82, 50])# You can dequeue like a queuefirst_item = numbers.popleft()  print(first_item) # 99  print(numbers) # deque([15, 82, 50])

执行结果

47deque([99, 15, 82, 50])99deque([15, 82, 50])

参考资料

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更严格的实现

创建撤消功能 - 允许用户回溯他们的操作，直到会话开始。堆栈是这种情况的理想选择。 我们可以通过将其推送到堆栈来记录用户所采取的每个操作。 当用户想要撤消操作时，他们将从堆栈中弹出它。

游戏中，每次按下按钮，都会触发输入事件。 测试人员注意到，如果按钮按下得太快，游戏只处理第一个按钮，特殊动作将无效！可以使用队列修复它。 我们可以将所有输入事件排入队列。

#!/usr/bin/python3# -*- coding: utf-8 -*-# 项目实战讨论QQ群630011153 144081101# python测试开发库汇总: https://github.com/china-testing/python-api-tesing/# 本文最佳板式地址： https://www.jianshu.com/p/c990427ca608# A simple class stack that only allows pop and push operationsclass Stack:    def __init__(self):        self.stack = []    def pop(self):        if len(self.stack) < 1:            return None        return self.stack.pop()    def push(self, item):        self.stack.append(item)    def size(self):        return len(self.stack)# And a queue that only has enqueue and dequeue operationsclass Queue:    def __init__(self):        self.queue = []    def enqueue(self, item):        self.queue.append(item)    def dequeue(self):        if len(self.queue) < 1:            return None        return self.queue.pop(0)    def size(self):        return len(self.queue)     document_actions = Stack()# The first enters the title of the documentdocument_actions.push('action: enter; text_id: 1; text: This is my favourite document')  # Next they center the textdocument_actions.push('action: format; text_id: 1; alignment: center')  # As with most writers, the user is unhappy with the first draft and undoes the center alignmentdocument_actions.pop()  # The title is better on the left with bold fontdocument_actions.push('action: format; text_id: 1; style: bold') input_queue = Queue()# The player wants to get the upper hand so pressing the right combination of buttons quicklyinput_queue.enqueue('DOWN')  input_queue.enqueue('RIGHT')  input_queue.enqueue('B')# Now we can process each item in the queue by dequeueing themkey_pressed = input_queue.dequeue() # 'DOWN'# We'll probably change our player positionkey_pressed = input_queue.dequeue() # 'RIGHT'# We'll change the player's position again and keep track of a potential special move to performkey_pressed = input_queue.dequeue() # 'B'# This can do the act, but the game's logic will know to do the special move