python类问题求助

wanggz100

In this task, we develop a class with which elements of a list can be used as often as desired, in cycles. The class Ez (short for "perpetual cycle") should have the following methods:

A constructor to pass any iterable (that is, list, tuple, ...). The default value of this iteration should be None.

A method set_data, which is also passed an Iterable. After calling set_data, this iterable should be used, starting with its first element.

A method next that provides a reference to the next element of the data. If no further data are available, the first element should be started again. When set_data is called, next should always start over again.

First write the constructor and set_data. Consider which attributes an object of this class must remember.
Then write the method next. If the iteration of the Ez object does not contain any elements, or if there is no Iterable, the method should return None.



#这些代码不能更改，用于检验
e = Ez([1,2,3])
assert e.next() == 1
assert e.next() == 2
assert e.next() == 3
assert e.next() == 1

BngThea

你的代码呢？只给题目？

wanggz100

BngThea 发表于 2017-11-23 16:48
你的代码呢？只给题目？

没有思路 不知道这个该怎么下手

BngThea

wanggz100 发表于 2017-11-23 16:50
没有思路 不知道这个该怎么下手

都告诉你类里面有哪些函数了，每个函数有什么功能了，至少能写出大致代码，完全没有思路那只能重新学习一下课程

wanggz100

BngThea 发表于 2017-11-23 16:53
都告诉你类里面有哪些函数了，每个函数有什么功能了，至少能写出大致代码，完全没有思路那只能重新学习一 ...

class Ez:
    def __init__(self,e):
        self.e = None

不知道这个 构造对不对

yjsx86

看介绍 完全是在写一个  generator

wanggz100

yjsx86 发表于 2017-11-23 17:25
看介绍 完全是在写一个  generator

怎么写 有没有提示。 我刚学一个月 没什么思路

ooxx7788

1. class EZ:
   
2.     def __init__(self, it):
   
3.         self.e = it
   
4.    
   
5.     def set_data(self):
   
6.         self.temp = (i for i in self.e)
   
7.    
   
8.     def next(self):
   
9.         try:
   
10.             return next(self.temp)
    
11.         except:
    
12.             self.set_data()
    
13.             return next(self.temp)
    
14. 
    
15. 
    
16. e = EZ([1, 2, 3])
    
17. assert e.next() == 1
    
18. assert e.next() == 2
    
19. assert e.next() == 3
    
20. assert e.next() == 1
    

复制代码

根据我的理解是这样的。