实现一个可迭代的类

 1 class Fabonacci(object):
 2     """Fabonacci Class
 3 
 4     Return Fabonacci Number
 5     """
 6     def __init__(self, num):
 7         self.num = num
 8         self.n, self.a, self.b = 0, 0, 1
 9 
10     def __iter__(self):
11         return self
12 
13     def next(self):
14         if self.n < self.num:
15             result = self.b
16             self.a, self.b = self.b, self.a+self.b
17             self.n = self.n + 1
18 
19             return result
20 
21         raise StopIteration()
22 
23 if __name__ == "__main__":
24 
25     fab = Fabonacci(5)
26 
27     for n in fab:
28         print n
29