一个迭代器的生成案例（明7暗7游戏）

class NumberGame:

    def __init__(self,start,stop):

        self.start = start

        self.stop = stop

        self.value = self.start - 1

        self.pacount = 0

    def __iter__(self):

        return self

    def __next__(self):

        if self.value == self.stop:

            raise StopIteration

        self.value = self.value + 1

        if self.value % 7 != 0 and str(self.value).find('7')==-1:

            return self.value

        else :

            self.pacount+=1

            return 'pa'

game = NumberGame(1,21)

for each in game:

    print(each,end=' ')