创建自己的迭代器

# -*- coding: utf-8 -*-

'''
创建自己的迭代器类，需要实现两个方法:
1. __iter__: The iter method simply returns a reference to the object itself and is always implemented to do so.
2. __next__: 
'''

class _BagIterator:
    
    def __init__(self, theList):
        self._bagItems = theList
        self._curItem = 0

    def __iter__(self):
        return self

    def __next__(self):
        if self._curItem < len(self._bagItems):
            item = self._bagItems[self._curItem]
            self._curItem += 1
            return item
        else:
            raise StopIteration