子手计划：循环验证

Question

I am writing a hangman game program in python and have run into a problem concerning validating loops. Here is an example of the type of problem:

    def loopGet():
        condition = True
        while condition == True:
            userInput = raw_input("Enter a string: ")
            # assigns boolean value to condition
            condition = ifWon()
            # returns condition
            return condition
            #assigns boolean value
            condition = ifLost()
            #return condition
            return condition

Pretending that ifWon() and ifLost() are already created, this is an example of what's going and what I am trying to figure out. In my program, even if both return True, the loop ends. If one returns True and the other False, it still ends. I am under the impression that if "condition" returns True, the loop should keep running; yes?

Answer 1

So basically you want to loop until ifWon() or ifLost() are True.

In the original code, when you 'return condition' outside an "if", you'll just leave the loop right away. In fact, you'll never reach ifLost(), because you'll just bail out in the line before that.

I don't think you need "condition" at all... just loop until you get to a True, and return then. Note how the returns are inside an if, so you only return if True.

  def loopGet():
    while True:
        userInput = raw_input("Enter a string: ")
        # do something with input
        if ifWon():
            return 'Won'
        if ifLost()
            return 'Lost'

Some people might object to the nested return, but that's a pretty straightforward way to do it.

Answer 2

The loop "ends" because the method's execution stops at the return statement. Since your return statement is inside your while loop, it appears that you condition is not working.

Once you move the return statement outside your loop, you'll get your expected results.

---

def game():

    isWinner = False
    while isWinner == False:
       # as the user for a guess
       # check the guess
       isWinner = isWon()
    return "You won!"

You set a variable to the condition that you want to change. So isWinner = False , then while isWinner == False: do your loop. If isWon() returns True or False , then in your while isWinner = isWon() . You don't need isLost() , as we want the loop to exit when the user has won.