Python while 循环不能在两个条件下工作

Question

Im trying to make a while loop that stops when two variables are equal to 0, but when one of them reaches 0 the loop ends, and I have no clue why. This is what I have...

  movement=3
  attacks=1
  while (attacks != 0) and (movement != 0):
    do = input('what to do?')
    if do == 'move':
      movement -=1
    if do =='attack':
      attacks -=1

I could be missing something obvious, but any help is appreciated

Answer 1

You had two mistakes in your code. The first one was you did not close your quotes in your input. The second was you used an assigning operator = instead of a comparison operator = on line 7 . Cleaned up code.

movement=3
attacks=1
while (attacks != 0) and (movement != 0):
    do=input('what to do?')
    if do=='move':movement-=1
    if do=='attack':attacks-=1

Answer 2

The loop will continue as long as the predicate (attacks != 0) and (movement != 0) is true. Therefore the loop will stop once the predicate is false. The predicate is false exactly when EITHER attacks == 0 OR movement == 0 . This is the negation of the predicate.

If you want the loop to end ONLY when both are 0, then you're saying you want the loop to continue as long as (attacks != 0) or (movement != 0) as the negation of that predicate is attacks == 0 and movement == 0 .

To find out more, see De Morgan's Laws

Answer 3

There are some syntax errors in your code, after fixing it it seems that in a while loop with 2 conditions doesn't work, here's a working version of it:

movement = 3
attacks = 1
while True:
    if attacks == 0 and movement == 0: break
    do = input('what to do?')
    if do == 'move':
        movement-=1
    if do == 'attack':
        attacks-=1

So you create an infinite loop and inside it you check if the attacks and movement are both equal to 0 , and if they're, then break out of the loop.