Python中的True和False布尔值

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. 

This is to show my understanding of Boolean. In the line testing next == "taunt bear" and not bear_moved , if my input is taunt bear , the result is True and True , which will continue the loop.

So what confused me is line testing next == "taunt bear" and bear_moved . If my input is taunt bear , is it suppose to be "taunt bear" == "taunt bear" and bear_moved which is True and True ? which means the loop will continue instead of cancelling it.

Answer 1

while True: will continue indefinitely (unless you put in a break - usually break is bad design in languages like Python)).

You probably want to do:

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

elif in python is equivilent to else if . If one of the elif blocks execute, none of the others can, and will jump to the bottom of the if .

After next == "taunt bear" and not bear_moved is executed and evaluates to true, and the block executes, control of the program continues back at the front of the loop and will ask for input again.