import re
import functools


def do_re(s, rdict):

    r = re.compile("|".join(rdict.keys()))
    return r.sub(lambda m: rdict[m.group(0)], s)


def do_str(s, rdict):

    return functools.reduce(lambda s, k: s.replace(k, rdict[k]), rdict, s)


if __name__ == "__main__":

    import timeit
    import itertools

    words = tuple(map("".join, itertools.product("abcdefg", repeat=5)))
    s = str.join(" ", words)
    rdict = {word: "yoba" for word in words}
    print(len(s))
    print(timeit.timeit(lambda: do_re(s, rdict), number=10))
    print(timeit.timeit(lambda: do_str(s, rdict), number=10))