Question

这个程序是我的GCSE计算机科学的蛇和梯子程序（不用担心，这只是练习），而且我在使用循环内部存在的函数打破while循环时遇到问题。这是代码：

win = False

while win == False:
    print("Player 1 goes first.")

    def dice():
        roll = random.randint(1,6)
        return roll

    roll = dice()
    print("They roll a...",roll)
    player1+=roll

    def check():
        if player1 in ladders or player2 in ladders:
            print("A ladder has moved the player to a new position.")
        elif player1 in snakes or player2 in snakes:
            print("A snake has moved the player to a new position.")
        elif player1 >= 36:
            print("Congratulations. Player 1 has won the game.")
            win = True
        elif player2 >= 36:
            print("Congratulations. Player 2 has won the game.")
            win = True

    check()

    print("Player 1 is on square",player1)

它显然还没有完成，而且并不是所有的代码。在那之后，它与播放器2一样。上面有一个元组，检查功能检查玩家是否落在蛇或梯子上，但我还没有添加实际上将玩家上下移动梯子/蛇的代码。 / p>

错误是while循环是一个无限循环。

我尝试将整个win = False或True更改为True，然后使用break我说win = True，然后它返回错误＆＃39; break out loop＆＃39;即使突破显然在循环内部。我不知道是不是因为我需要从函数中返回一些东西，但我不太清楚该怎么做。简单地说“返回胜利”＃39;下面两个win = True并没有改变任何东西，而while循环仍然无限期地继续。

我看了here和here的答案，但都没有为我工作;我认为我的情况略有不同。

Answer 1

之所以发生这种情况是因为当您在函数中赋值变量时，它使用局部变量。因此，为了快速修复，您可以在检查功能中添加global win：

def check():
    global win
    if player1 in ladders or player2 in ladders:
        print("A ladder has moved the player to a new position.")
    elif player1 in snakes or player2 in snakes:
        print("A snake has moved the player to a new position.")
    elif player1 >= 36:
        print("Congratulations. Player 1 has won the game.")
        win = True
    elif player2 >= 36:
        print("Congratulations. Player 2 has won the game.")
        win = True

您可以在此处详细了解变量类型 - http://www.python-course.eu/python3_global_vs_local_variables.php

同样，将函数存储在内部并不是一个好主意，因为它会在每次迭代时创建函数，这是不好的。所以更好的是在循环之外定义它们。

Answer 2

也许这就是你要找的东西？注意我是如何将这些函数从循环中取出来的。然后我完全抛弃了一个布尔变量，因为它有更简洁的方法。如果满足特定条件，您可以使用while True，然后只使用break。如果您希望循环在满足特定条件时返回起点，则可以使用continue。

def dice():
        return random.randint(1,6)


def check():
        if player1 in ladders or player2 in ladders:
            print("A ladder has moved the player to a new position.")
        elif player1 in snakes or player2 in snakes:
            print("A snake has moved the player to a new position.")
        elif player1 >= 36:
            print("Congratulations. Player 1 has won the game.")
            return True
        elif player2 >= 36:
            print("Congratulations. Player 2 has won the game.")
            return True

while True:
    print("Player 1 goes first.")

    roll = dice()
    print("They roll a...",roll)
    player1 += roll

    if check():
        break

    print("Player 1 is on square",player1)

我没有触及逻辑，但将玩家得分传递给check会有意义。

无法在函数内循环时断开python

2 个答案: