Get Python list in chunks

chunker.py

#!/usr/bin/env python

import unittest


## get a list in chunks
## if we run out of items in the list, start again from the beginning

class Chunker(object):

    def __init__(self,flist,chunk_size):

        self.current_pos=0
        self.flist=flist
        self.chunk_size=chunk_size


    def next(self):

        endpos = self.current_pos+self.chunk_size
        sublist = self.flist[self.current_pos:endpos]

        if len(sublist)<self.chunk_size:

            items_short=self.chunk_size-len(sublist)
            sublist+=self.flist[0:items_short]
            self.current_pos=items_short
        else:
            self.current_pos=endpos

        return sublist




class TestChunker(unittest.TestCase):

    def test_get_list(self):

        lst = range(10)

        c = Chunker(lst,7)

        self.assertEquals(range(7),c.next())

    def test_get_rollover(self):

        lst = range(10)

        c = Chunker(lst,7)

        self.assertEquals(range(7),c.next())

        next = c.next()

        self.assertEquals(7,len(next))

        self.assertEquals([7,8,9,0,1,2,3],next)

        self.assertEquals([4,5,6,7,8,9,0],c.next())


if __name__=='__main__':

    unittest.main()