Python中的True和False布爾值

Question

bear_moved = False 

while True: 
    next = raw_input("> ") 

    if next == "take honey": 
        dead("The bear looks at you then slaps your face off.") 
    elif next == "taunt bear" and not bear_moved: 
        print "The bear has moved from the door. You can go through." 
        bear_moved = True 
    elif next == "taunt bear" and bear_moved: 
        dead("The bear gets pissed off and chews your leg off.") 
    elif next == "open door" and bear_moved: 
        gold_room() 
    else: 
        print "I got no idea what that means. 

這是為了顯示我對布爾的理解。 next == "taunt bear" and not bear_moved的行測試中，如果我的輸入是taunt bear ，結果為True and True ，它將繼續循環。

所以讓我感到困惑的是， next == "taunt bear" and bear_moved線測試next == "taunt bear" and bear_moved 。 如果我的輸入是taunt bear ，是否應該是"taunt bear" == "taunt bear"和bear_moved ，分別為True and True ？ 這意味着循環將繼續而不是取消循環。

Answer 1

while True:會無限期繼續（除非您稍作break -通常， break是Python等語言中的不良設計）。

您可能想做：

while something == True: #Or - as has been pointed out, `while something` - which is equivalent and more Pythonic
    ...
    some code which eventually sets something to False
    ...

Answer 2

python中的elif等價於else if 。 如果執行其中一個elif塊，則其他任何一個都不能執行，並將跳至if的底部。

在執行next == "taunt bear" and not bear_moved並評估為true，然后執行該塊后，對程序的控制在循環的最前面繼續，並再次請求輸入。