Python 3 剪刀石头布问题

Question

我正在做一个石头、剪刀、布的游戏作为编程作业，但遇到了一些问题。这个程序应该让用户选择四个选项中的一个：1) 石头，2) 布，3) 剪刀，4) 退出。玩家选择一个选项后，程序会显示电脑的选择，并宣布谁是赢家，然后询问你是否想再玩一局。如果选择“y”，就会返回主菜单选择另一个选项，选择其他任何东西则会显示赢了多少局、输了多少局以及平局的局数。如果玩家选择4，程序应该显示“正在退出程序...”并展示游戏结果。

我遇到的问题有：

1. 第一次选择后，赢家会被显示，程序会返回主菜单。如果你进行第二次选择，程序会告诉你电脑选择了什么，然后问你是否想再玩一次。选择“y”会让你回到主菜单，但电脑的选择不会改变，无论你选择什么，游戏的结果总是和第一次一样。如果你选择不再玩，赢、输和平局的局数会显示出来（这部分似乎是正常工作的）。

2. 退出选项会让你返回主菜单，而不是显示游戏结果。我不太确定应该把那个判断语句放在哪里。

如果能帮我解决这些问题，我会很感激。

谢谢

#import module
import random

def main():
    #create a variable to control the loop
    play_again = 'y'

    #create a counter for tied games, computer games and player games
    tied_games = 0
    computer_games = 0
    player_games = 0

    #display opening message
    print("Let's play rock, paper scissors!") 

    computer_choice = process_computer_choice()

    player_choice = process_player_choice()

    winner = determine_winner(player_choice, computer_choice)

    #setup while loop for playing multiple games
    while play_again == 'y' or play_again == 'Y':

        process_computer_choice()

        process_player_choice()

        #use a if else statement to print the computers choice
        if computer_choice == 1:
            print('computer chooses rock.')

        elif computer_choice == 2:
            print('computer chooses paper.')

        else:
            print('computer chooses scissors.')

            #call the determine winner function    
            determine_winner(player_choice, computer_choice)

        #check who won the game and add 1 to the correct counter
        if winner == 'computer':
            computer_games += 1

        elif winner == 'player':
            player_games += 1

        else:
            tied_games += 1

        #ask the user if they would like to play again    
        play_again = input('would you like to play again? (enter y for yes): ')

    #display number of games that were won by the computer, the player and that were tied
    print()
    print('there was', tied_games, 'tied games.')
    print('the player won', player_games, 'games.')
    print('The computer won', computer_games,'games.')

#define the process computer function
def process_computer_choice():

    #setup computer to select random integer between 1 and 3
    choice1 = random.randint(1, 3)

    #return the computers choice
    return choice1

#define the process player function
def process_player_choice():

    #add input for players choice
    print()
    print('        MENU')
    print('1) Rock!')
    print('2) Paper!')
    print('3) Scissors!')
    print('4) Quit')
    print()

    player_choice = int(input('Please make a selection:  '))

    #add if statement for quit option
    if player_choice == 4:
        print('Exiting program....')

   #validate if the user enters a correct selection
    while player_choice != 1 and player_choice != 2 and player_choice != 3 and player_choice != 4:

        #print a error message if the wrong selection is entered
        print('Error! Please enter a correct selection.')

        player_choice = int(input('Please make a selection: '))

    #return the players choice
    return player_choice

#define the determine winner function
def determine_winner(player_choice, computer_choice):

    #setup if else statements for each of the 3 computer selections
    if computer_choice == 1:
        if player_choice == 2:
            print('Paper wraps rock. You win!')
            winner = 'player'

        elif player_choice == 3:
            print('Rock smashes scissors. The computer wins!')
            winner = 'computer'

        else:
            print('The game is tied. Try again.')
            winner = 'tied'

    if computer_choice == 2:
        if player_choice == 1:
            print('Paper wraps rock. The computer wins!')
            winner = 'computer'

        elif player_choice == 3:
            print('Scissors cut paper. You win!')
            winner = 'player'

        else:
            print('The game is tied. Try again.')
            winner = 'tied'

    if computer_choice == 3:
        if player_choice == 1:
            print('Rock smashes scissors. You win!')
            winner = 'player'

        elif player_choice == 2:
            print('Scissors cut paper. The computer wins!')
            winner = 'computer'

        else:
            print('The game is tied. Try again.')
            winner = 'tied'

    return winner

main()

Answer 1

你没有再次给 computer_choice 或 player_choice 赋值，而是直接使用它们的值。

while play_again == 'y' or play_again == 'Y':

    process_computer_choice()

    process_player_choice()

应该是这样的：

while play_again == 'y' or play_again == 'Y':

    computer_choice = process_computer_choice()

    player_choice = process_player_choice()

至于退出的部分，只需要在选择退出时使用 break。你需要在 process_player_choice 函数中提前返回，同时在 main 函数中也要做一些处理。

所以在 process_player_choice 函数中：

if player_choice == 4:
    print('Exiting program....')
    return

在 main 函数中：

player_choice = process_player_choice()

if player_choice == 4:
     return 

winner = determine_winner(player_choice, computer_choice)

#setup while loop for playing multiple games
while play_again == 'y' or play_again == 'Y':

    computer_choice = process_computer_choice()

    player_choice = process_player_choice()
    if player_choice == 4:
         break

Answer 2

对于第一个问题，是因为你在循环开始之前就设置了电脑和玩家的选择，而且从来没有更新它们。你可以把循环开始的部分改成：

while play_again == 'y' or play_again == 'Y':
    computer_choice = process_computer_choice()
    player_choice = process_player_choice()

你也可以删掉循环前面那些检查输入和赢家的代码，因为在第一轮的时候，这些代码其实是多余的。

对于第二个问题，只需要在选择了4之后添加结果，像这样：

if player_choice == 4:
      print('Exiting program....')  
      print('there was', tied_games, 'tied games.')
      print('the player won', player_games, 'games.')
      print('The computer won', computer_games,'games.')
      sys.exit() # be sure you add 'import sys' to the beginning of your file

另外，你在主循环中的那行代码 determine_winner(player_choice, computer_choice) 缩进了，这样只有在电脑选择剪刀的时候才会被调用，所以你应该把它的缩进去掉 :)