[已解决]python 课后作业42讲动动手2的右移为什么不右移

朱谊洪

class Nstr(str):
    def __lshift__(self,other):
        return self[other:] + self[:other]

    def __rshift__(self,other):
        return self[:-other] + self[-other:]


>>> a = Nstr('xiao jia yu!')
>>> a<<3
'o jia yu!xia'
>>> a>>2
'xiao jia yu!'
>>>
为什么他不右移？？？

最佳答案

月排行榜 / 总排行榜

hldh214

2016-2-20 16:11:40

因为你的__rshift__()方法定义错误
正确的定义:

1. class Nstr(str):
   
2.     def __lshift__(self,other):
   
3.         return self[other:] + self[:other]
   
4. 
   
5.     def __rshift__(self,other):
   
6.         return self[-other:] + self[:-other]
   
7. 
   
8. >>> a = Nstr('xiao jia yu!')
   
9. >>> a<<3
   
10. 'o jia yu!xia'
    
11. >>> a>>3
    
12. 'yu!xiao jia '

复制代码

跳转到最佳答案楼层

hldh214

因为你的__rshift__()方法定义错误
正确的定义:

1. class Nstr(str):
   
2.     def __lshift__(self,other):
   
3.         return self[other:] + self[:other]
   
4. 
   
5.     def __rshift__(self,other):
   
6.         return self[-other:] + self[:-other]
   
7. 
   
8. >>> a = Nstr('xiao jia yu!')
   
9. >>> a<<3
   
10. 'o jia yu!xia'
    
11. >>> a>>3
    
12. 'yu!xiao jia '

复制代码