1 class Foo: 2 def __init__(self,x): 3 self.x = x 4 def __iter__(self): 5 return self 6 def __next__(self): 7 if self.x == 15: 8 raise StopIteration('数字过大') #抛出异常 9 self.x += 1 10 return self.x 11 12 f1 = Foo(10) 13 print(f1.__next__()) #11 14 print(f1.__next__()) #12 15 print(f1.__next__()) #13 16 print(next(f1)) #14 17 print(next(f1)) #15 18 print(next(f1)) #StopIteration: 数字过大 19 for i in f1: 20 print(i) 21 # 11 22 # 12 23 # 13 24 # 14 25 # 15 26 27 ## 迭代器实现斐波那契数列 28 class Foo: 29 def __init__(self): 30 self._a = 1 31 self._b = 1 32 def __iter__(self): 33 return self 34 def __next__(self): 35 if self._a > 100: 36 raise StopIteration('程序终止') 37 self._a,self._b = self._b,self._a + self._b 38 return self._a 39 f1 = Foo() 40 print(f1.__next__()) 41 print(f1.__next__()) 42 print(f1.__next__()) 43 print(f1.__next__()) 44 print(f1.__next__()) 45 print(f1.__next__()) 46 print('-------------') 47 for i in f1: #for循环遍历f1是接着上面的内容继续，不会从头开始也不会往回返 48 print(i)