Question

我正在为学校做一个基本的石头剪刀代码，但我的elif陈述没有运行。

def player1(x):
    while x != 'rock' and x != 'paper' and x != 'scissors':
        print("This is not a valid object selection")
        x = input("Player 1? ")

def player2(x):
    while x != 'rock' and x != 'paper' and x != 'scissors':
        print("This is not a valid object selection")
        x = input("Player 2? ")

def winner():
    player1(input("Player 1? "))
    player2(input("Player 2? "))
    if player1 == 'rock' and player2 == 'rock':
        print('Tie')
    elif player1 == 'paper' and player2 == 'paper':
        print('Tie')
    elif player1 == 'rock' and player2 == 'paper':
        print('Player 2 wins')
    elif player1 == 'paper' and player2 == 'rock':
        print('Player 1 wins')
    elif player1 == 'rock' and player2 == 'scissors':
        print('Player 1 wins')
    elif player1 == 'scissors' and player2 == 'rock':
        print('Player 2 wins')
    elif player1 == 'paper' and player2 == 'scissors':
        print('Player 2 wins')
    elif player1 == 'scissors' and player2 == 'paper':
        print('Player 1 wins')
    elif player1 == 'scissors' and player2 == 'scissors':
        print('Tie')

winner()

当我运行此代码时，它会要求播放器1？＆＃39;并且除了摇滚，纸张或剪刀之外别无他法。然后它继续为player2做同样的事情。但是，这是代码结束的地方，它不会运行我的elif语句并打印哪个玩家获胜。

编辑：已解决。感谢您帮助初学者。我完全忘记返回字符串并将它们分配给变量。

Answer 1

分配到player1内的x并不是在做任何事情。函数返回后，将删除分配给x的值。这意味着你丢弃了你的输入！然后，您将函数 player1与字符串进行比较，这些字符串可能与您的输入相匹配。

调试建议：每当出现控制流问题时，请打印出控制变量。在这里，如果你打印player1，你会看到令人惊讶的东西。

Answer 2

您的比较：

elif player1 == "rock" and player2 == "rock":
# etc

总是会失败，因为player1和player2都是函数。

相反，您需要从函数返回并将它们分配给变量。让我们在一分钟内完成验证并稍微减少一点。

def choose(prompt):
    return input(prompt)

def winner(a, b):
    if a == 'rock':
        if b == 'rock': return None
        elif b == 'paper': return 2
        elif b == 'scissors': return 1
    elif a == 'paper':
        # etc

def play_game():
    p1_choice = choose("Player 1: ")
    p2_choice = choose("Player 2: ")
    return winner(p1_choice, p2_choice)

请注意，对于这些elif链来说，一个看起来更漂亮的技巧是将它们放在字典中并将索引编入索引。

RESULT_DICT = {"rock": {"rock": None,
                        "paper": 2,
                        "scissors": 1},
               "paper": {"rock": 1,
                         "paper": None,
                         "scissors": 2},
               "scissors": {"rock": 2,
                            "paper": 1,
                            "scissors": None}}

def winner(a, b):
    return RESULT_DICT[a][b]

Elif声明不打印

2 个答案: