python -- iterator

iterator.py

class SkipIterator(object):
    def __init__(self, wrapped):
        self.wrapped = wrapped
        self.offset = 0

    def __next__(self):
        if self.offset == len(self.wrapped):
            raise StopIteration
        else:
            item = self.wrapped[self.offset]
            self.offset += 2
            return item

    def __iter__(self):
        return self

    def next(self):
        return self.__next__()


class IterObject(object):
    def __init__(self, wrapped):
        self.wrapped = wrapped

    def __iter__(self):
        return SkipIterator(self.wrapped)


class IterAll(object):
    def __init__(self, data):
        self._data = data

    def __iter__(self):
        print 'iterator'
        self._index = 0
        return self

    def __next__(self):
        if self._index == len(self._data):
            raise StopIteration
        item = self._data[self._index]
        self._index += 1
        return item

    def next(self):
        return self.__next__()

    def __getitem__(self, index):
        print 'indexed from get item'
        return self._data[index]

    def __contains__(self, value):
        return value in self._data

if __name__ == '__main__':
    l = IterObject('abcdef')
    print [x + y for x in l for y in l]
    # print l
    it = IterAll([1, 2, 3, 4, 5, 6, 7])
    print [x for x in it]
    print it[0]