New in version 2.2.
iterator.__iter__()
Return the iterator object itself. This is required to allow both containers and iterators to be used with the for and instatements. This method corresponds to the tp_iter slot of the type structure for Python objects in the Python/C API.
iterator.next()
Return the next item from the container. If there are no further items, raise the StopIteration exception. This method corresponds to the tp_iternext slot of the type structure for Python objects in the Python/C API.
也就是说 __iter__与next()是配套使用的。
Fibonacci数列：
#!/usr/bin/python
# -*- coding: utf-8 -*-
class Fibo(object):
def __init__(self):
self.a, self.b = 0, 1
def __iter__(self):
return self
def __next__(self):
self.a, self.b = self.b, self.a + self.b
if self.a > 10000:
raise StopIteration()
return self.a, self.b
for n in Fibo():
print n
运行失败：
怎么用class做才能成功呢？？？？？
后来，才发现，我2.7版本的解释器不支持，用网页上的Python3在线编程解释器完美运行。。。。。。is ri le gou le.
附使用的python3环境：http://www.dooccn.com/python3/
请问各位大佬，在2.7版本中我该怎么使用 __iter__ 呢？？求教！！！
python Class: 面向对象高级编程 __iter__ 和 next()
原文：http://blog.51cto.com/13502993/2147531