如何只使某个条件在方法中运行一次？

Question

I only want val to be 0 the first time I run the method but I can't figure out a way to do this. The first time the method is ran the value rolled equals the value, then the user has to roll the value plus one. If the user does not roll the next value, 'You rolled a {} but needed to roll a {}' is displayed. If they get the correct roll then 'You got it! Next value is {}' will be displayed.

def roll(self):
        'primary game play'
        ds.shake()
        rolled = ds.getTotalRoll()
        while True:
            val = 0
            if val == 0:
                rolled = val
                val += 1
                return 'You got it! Next value is {}'.format(val)
                break
        if rolled == val:
            val +=1
            self.count += 1
            return 'You got it! Next value is {}'.format(val)
        else:
            self.count += 1
            return 'You rolled a {} but needed to roll a {}'.format(rolled, val)

Answer 1

Make it an object property and set it in the constructor.

def __init__(self):
    self.val = 0
    ...

def roll(self):
    'primary game play'
    ds.shake()
    rolled = ds.getTotalRoll()
    while True:
        if self.val == 0:
            rolled = self.val
            self.val += 1
            return 'You got it! Next value is {}'.format(self.val)
            break
    if rolled == self.val:
        self.val +=1
        self.count += 1
        return 'You got it! Next value is {}'.format(self.val)
    else:
        self.count += 1
        return 'You rolled a {} but needed to roll a {}'.format(rolled, self.val)