Sum Dictionary Tuples

merge.py

import operator

def merge(dicts):
    result = {}
    keys = reduce(operator.or_, [set(d) for d in dicts])
    for key in keys:
        values = [d[key] for d in dicts if key in d]
        result[key] = tuple(reduce(operator.add, x) for x in zip(*values))
    return result

if __name__ == '__main__':
    a = {0: (1, 3, 2), 1: (8, 4, 4), 2: (3, 4, 2)}
    b = {0: (5, 5, 6), 1: (3, 7, 6), 2: (1, 9, 5)}
    c = {0: (3, 7, 7), 1: (2, 3, 8)}
    print merge([a, b, c]) # {0: (9, 15, 15), 1: (13, 14, 18), 2: (4, 13, 7)}