迭代器实现斐波纳契数列

斐波纳契数列特点:后一位数字是前两个数字的和

class Fib:
    def __init__(self):
        self._a = 1
        self._b = 1

    def __iter__(self):
        return self

    def __next__(self):
        if self._a > 1000:
            raise StopIteration
        self._a,self._b = self._b,self._a + self._b
        return self._a

f1 = Fib()

for i in f1:
    print(i)

效果图: