#!/usr/bin/env python

import operator

def groupdict(dict, match_func=operator.eq):
    """Groups similar dictionary values by key

    >>> groupdict({1: 'a', 3: 'a', 4: 'b', 5: 'c', 6: 'a', 7: 'b', 8: 'a'})
    [[1, 3, 6, 8], [4, 7], [5]]
    """
    groups = []
    ids = dict.keys()
    while ids:
        group = [ids[0]]
        groups.append(group)
        val = dict[ids[0]]
        for id in ids[1:]:
            if match_func(val, dict[id]):
                group.append(id)
        for id in group:
            ids.remove(id)
    return groups

if __name__ == '__main__':
    import doctest
    import sys
    sys.exit(doctest.testmod().failed)