带有或条件的while循环答案

【问题标题】：while loop with or condition带有或条件的while循环
【发布时间】：2018-06-11 12:12:14
【问题描述】：

在第二个 while 循环中，我被卡住了，永远无法摆脱。如何解决？

def playGame(wordList):

new_hand = {}

choice = input('Enter n to deal a new hand, or e to end game: ')   
while choice != 'e':
    if choice == 'n':
        player_or_pc = input('Enter u to have yourself play, c to have the computer play: ')
        while player_or_pc != 'u' or player_or_pc != 'c':
            print('Invalid command.')
            player_or_pc = input('Enter u to have yourself play, c to have the computer play: ')                  
        if player_or_pc == 'u':
            print('player played the game')
        elif player_or_pc == 'c':
            print('PC played the game')
        choice = input('Enter n to deal a new hand, r to replay the last hand, or e to end game: ')
    else:
        print('Invalid command.')
        choice = input('Enter n to deal a new hand, r to replay the last hand, or e to end game: ')

【问题讨论】：

player_or_pc != 'u' or player_or_pc != 'c' - 此条件将始终为真。听起来你想要 and 而不是 or。

标签： python while-loop logical-operators

【解决方案1】：

player_or_pc != 'u' or player_or_pc != 'c'总是正确的：

如果player_or_pc是'u'，则不等于'c'，所以两个条件之一为真
如果player_or_pc是'c'，不等于'u'，所以两个条件之一为真
任何其他值两个条件都为真

使用and：

while player_or_pc != 'u' and player_or_pc != 'c':

或者用==，把整体放在括号里，前面用not：

while not (player_or_pc == 'u' or player_or_pc == 'c'):

此时使用会员测试更清楚：

while player_or_pc not in {'u', 'c'}:

【讨论】：

【解决方案2】：

替换

while player_or_pc != 'u' or player_or_pc != 'c':

与

while player_or_pc != 'u' and player_or_pc != 'c':

否则，player_or_pc 应该等于 u 和 c，这是不可能的。

【讨论】：