### 自己创建一个可以迭代的类： ``` class MyNumbers: def __iter__(self): self.a = 1 return self def __next__(self): x = self.a self.a += 1 return x myclass = MyNumbers() myiter = iter(myclass) print(next(myiter)) print(next(myiter)) print(next(myiter)) ``` 防止无限迭代下去,使用raise StopIteration即可。 ``` class MyNumbers: def __iter__(self): self.a = 1 return self def __next__(self): x = self.a self.a += 1 if x < 100: return x ## 防止无限迭代下去 else: raise StopIteration ```