Python基础30类-内置函数实现迭代器协议

#内置方法实现迭代器协议
class test_iter:
    def __init__(self,n):
        self.n=n
    def __iter__(self):
        return self
    def __next__(self):
        if self.n == 100:
            raise StopIteration('终止了')
        self.n+=1
        return self.n
test_iter1=test_iter(10)
print(next(test_iter1))
#斐波那契数列
class Fib:
    def __init__(self):
        self.a=1
        self.b=1
    def __iter__(self):
        return self
    def __next__(self):
        self.a,self.b = self.b,self.a+self.b
        return self.a
fib1=Fib()
print(next(fib1))
print(next(fib1))
print(next(fib1))
print(next(fib1))
for i in fib1:
    print(i)