Filter lists in python

getunique.py

#!/usr/bin/env python

from itertools import imap, groupby
from operator import itemgetter


def _unique_justseen(iterable, key=None):
    """List unique elements, preserving order.
    Remember only the element just seen."""

    # unique_justseen('AAAABBBCCDAABBB') --> A B C D A B
    # unique_justseen('ABBCcAD', str.lower) --> A B C A D
    return imap(next, imap(itemgetter(1), groupby(iterable, key)))


if __name__ == '__main__':

    a = 'AAAABBBCCDAABBB'
    print a
    print list(_unique_justseen(a)), '\n'

    b = [(4,5),(4,4),(5,3),(4,5),(4,5)]
    print b
    print list(_unique_justseen(b), ), '\n'

    grouping = lambda x: x[0]
    print b
    print list(_unique_justseen(b, key=grouping)), '\n'