Split list into number of Pieces

Today, while working with csv files i got into fantastic situation where i have a list of million values and i make iteration on that. So i thought, it would be easy for me if i split list into number of pieces which dont affect my code, memory and CPU. I can also use generator expression to make make my code run faster, but i was very curious to write code to split list into number of pieces(uses little of generator exp).
And the result is here -


    import os,sys

    def split_seq(seq, num_pieces):
        """ split a list into pieces passed as param """
        start = 0
        for i in xrange(num_pieces):
            stop = start + len(seq[i::num_pieces])
            yield seq[start:stop]
            start = stop

    seq = [i for i in range(100)]   ## define your list here
    num_of_pieces = 3
    for seq in split_seq(seq, num_of_pieces):
        print len(seq), '-> ',seq

Dynamicaly open file

Recently i had gone through a situation like to split a 40GB csv file for further processing, into 60 pieces having name/content to be decided dynamically based on a id present in that csv file. That really make me to write some little code to open/write/close file dynamically. I wrote following code to achieve this.

import os, sys
a=range(10)
for each in a:
    s = "fl_%s = open('%s','a')" % (each,each)
    exec s
    exec "fl_%s.write('%s')" % (each,each)
    com = "fl_%s.close()" % (each)
    exec com
    # can also check if file is closed or open by
    # com = "fl_%s.closed" % (each)
    # bool(com) #return true if file is closed else false