迭代器协议item 和裴波拉切数列

 1 class Runf:
 2     
 3     def __init__(self,n):
 4         self.n=n
 5     # def __iter__(self):
 6     #     return  self
 7 
 8     def __next__(self):
 9         if self.n==12:
10          raise StopIteration("程序异常终止了！")
11         self.n+=1
12         return self.n
13 
14 rf=Runf(10)
15 
16 # for i in rf:
17 #     print(i)
18 print(next(rf))
19 print(next(rf))
20 # print(next(rf)) #大于12抛异常
21

裴波拉切数列：

 1 class Runf:
 2 
 3     def __init__(self):
 4         self._a=1
 5         self._b=1
 6     def __iter__(self):
 7         return  self
 8 
 9     def __next__(self):
10         self._a,self._b=self._b,self._a+self._b
11         return self._a
12 
13 rf=Runf()
14 # print(rf.__next__())
15 # print(rf.__next__())
16 # print(rf.__next__())
17 # print(rf.__next__())
18 # print(rf.__next__())
19 # print(rf.__next__())
20 for i in rf:
21     print(i)    #迭代器实现裴波拉切
22 
23 
24 
25 lis=[]
26 for i in range(10):
27     if i==0 or i==1:
28         lis.append(1)
29     else:
30         lis.append(lis[i-2]+lis[i-1])
31 print(lis)      #递归实现裴波拉切
32 
33 a=0
34 b=1
35 while b<60:
36    print(b)
37    a,b=b,a+b   #while循环实现

裴波拉切