[小知识]Python迭代器相关 @ Python

class Fib(object):
    def __init__(self):
        self.a, self.b = 0, 1 # 初始化两个计数器a，b

    def __iter__(self):
        return self # 实例本身就是迭代对象，故返回自己

    def next(self):
        self.a, self.b = self.b, self.a + self.b # 计算下一个值
        if self.a > 100000: # 退出循环的条件
            raise StopIteration();
        return self.a # 返回下一个值

>>> for n in Fib():
...     print n
...
1
1
2
3
5
...
46368
75025

f = Fib()
for i in range(10):
    print f.next()

1
1
2
3
5
8
13
21
34
55

class A(object):

    def __init__(self, o):
        self.__obj__ = o

    def __getattr__(self, name):
        if hasattr(self.__obj__, name):
            return getattr(self.__obj__, name)
        return self.__dict__[name]

    def __iter__(self):
        return self.__obj__.__iter__()

l = []
a = A(l)

for i in xrange(101): a.append(i)

print sum(a)