27-小程序_石头、纸、剪刀

2.11　小程序：石头、纸、剪刀

让我们利用前面学到的编程概念，创建一个简单的“石头、纸、剪刀”游戏。输出结果如下所示：

ROCK,  PAPER,  SCISSORS
0 Wins, 0 Losses, 0 Ties
Enter your move: (r)ock (p)aper (s)cissors or (q)uit
p
PAPER versus... 
PAPER
It is a tie! 
0 Wins, 1 Losses, 1 Ties
Enter your move: (r)ock (p)aper (s)cissors or (q)uit
s
SCISSORS  versus...
PAPER
You win! 
1 Wins, 1 Losses, 1 Ties
Enter your move: (r)ock (p)aper (s)cissors or (q)uit
q

在文件编辑器中输入以下源代码，并将文件另存为rpsGame.py：

import  random,  sys
print('ROCK,  PAPER,  SCISSORS') 
# These variables keep track of the number of wins, losses, and ties.
wins = 0
losses  =  0
ties = 0
while  True:  #  The  main  game  loop. 
    print('%s  Wins,  %s  Losses,  %s  Ties'  %  (wins,  losses,  ties)) 
    while True: # The  player input loop. 
        print('Enter your move: (r)ock (p)aper (s)cissors or (q)uit')
        playerMove = input()
        if playerMove == 'q': 
             sys.exit()  #  Quit  the  program. 
        if playerMove == 'r' or playerMove == 'p' or playerMove == 's':
             break  #  Break  out  of  the  player  input  loop. 
        print('Type one of r, p, s, or q.') 
    # Display what the player chose: 
    if playerMove == 'r': 
         print('ROCK versus...') 
    elif playerMove == 'p': 
         print('PAPER versus...') 
    elif playerMove == 's': 
         print('SCISSORS versus...') 
    # Display what the computer chose:
    randomNumber = random.randint(1, 3) 
    if randomNumber == 1: 
        computerMove = 'r' 
        print('ROCK') 
    elif randomNumber == 2:
         computerMove = 'p'
         print('PAPER') 
    elif randomNumber == 3:
         computerMove = 's'
         print('SCISSORS') 
    # Display and record the win/loss/tie: 
    if playerMove == computerMove: 
        print('It  is  a  tie!') 
        ties = ties + 1
    elif playerMove == 'r' and computerMove == 's':
        print('You   win!') 
       wins  =  wins  +  1
    elif playerMove == 'p' and computerMove == 'r':
        print('You   win!') 
       wins  =  wins  +  1
    elif playerMove == 's' and computerMove == 'p':
        print('You   win!') 
       wins  =  wins  +  1
    elif playerMove == 'r' and computerMove == 'p':
        print('You  lose!') 
       losses  =  losses  +  1
    elif playerMove == 'p' and computerMove == 's':
        print('You  lose!')
        losses  =  losses  +  1
    elif playerMove == 's' and computerMove == 'r':
        print('You lose!') 
        losses  =  losses  +  1

我们从头开始逐行查看这段代码。

import  random,  sys
print('ROCK,  PAPER,  SCISSORS')
# These variables keep track of the number of wins, losses, and ties.
wins = 0
losses  =  0
ties = 0

首先，导入 random 和 sys 模块，以便程序可以调用 random.randint() 和 sys.exit() 函数。我们还设置了3个变量来跟踪玩家所获得的胜利、失败和平局。

while  True:  #  The  main  game  loop. 
    print('%s  Wins,  %s  Losses,  %s  Ties'  %  (wins,  losses,  ties)) 
    while True: # The  player input loop. 
        print('Enter your move: (r)ock (p)aper (s)cissors or (q)uit')
        playerMove = input()
        if playerMove == 'q': 
             sys.exit()  #  Quit  the  program. 
        if playerMove == 'r' or playerMove == 'p' or playerMove == 's': 
              break  #  Break  out  of  the  player  input  loop. 
        print('Type one of r, p, s, or q.') 

该程序在一个 while 循环内使用了另一个 while 循环。第一个循环是主程序循环，在这个循环的每次迭代中，玩家玩一局石头、纸和剪刀游戏。第二个循环要求玩家输入，并一直循环，直到玩家输入 r 、 p 、 s 或 q 作为其选择。 r 、 p 和 s 分别对应于石头、纸和剪刀；而 q 则表示玩家打算退出，在这种情况下，将调用 sys.exit() 函数并退出程序。如果玩家输入了 r 、 p 或 s ，则执行会跳出循环；否则，程序会提醒玩家输入 r 、 p 、 s 或 q ，然后返回循环的起点。

    # Display what the player chose: 
    if playerMove == 'r':
     print('ROCK versus...') 
    elif playerMove == 'p': 
     print('PAPER versus...') 
    elif playerMove == 's': 
     print('SCISSORS versus...') 

玩家的选择会显示在屏幕上。

    # Display what the computer chose: 
    randomNumber = random.randint(1, 3) 
    if randomNumber == 1: 
     computerMove = 'r' 
     print('ROCK') 
    elif randomNumber == 2: 
     computerMove = 'p' 
     print('PAPER') 
    elif randomNumber == 3:
     computerMove = 's' 
     print('SCISSORS') 

接下来，随机选择计算机的选择。由于 random.randint() 函数只能返回随机数，因此它返回的整数值1、2或3存储在名为 randomNumber 的变量中。程序根据 randomNumber 中的整数，在 computerMove 中存储 'r' 、 'p' 或 's' 字符串，并显示计算机的选择。

    # Display and record the win/loss/tie: 
    if playerMove == computerMove: 
     print('It  is  a  tie!')
     ties = ties + 1
    elif playerMove == 'r' and computerMove == 's': 
     print('You   win!') 
     wins  =  wins  +  1
    elif playerMove == 'p' and computerMove == 'r': 
     print('You   win!')
     wins  =  wins  +  1
    elif playerMove == 's' and computerMove == 'p':
     print('You   win!')
     wins  =  wins  +  1
    elif playerMove == 'r' and computerMove == 'p': 
     print('You  lose!')
     losses  =  losses  +  1
    elif playerMove == 'p' and computerMove == 's':
     print('You  lose!')
     losses  =  losses  +  1
    elif playerMove == 's' and computerMove == 'r': 
     print('You lose!')
     losses  =  losses  +  1

最后，该程序比较 playerMove 和 computerMove 中的字符串，并将结果显示在屏幕上。它还会相应增加 wins 、 losses 或 ties 变量的值。一旦执行结束，它将跳回到主程序循环的开始处，开始另一局游戏。