# mode_finder.py -- V.1.0, Feb 14 2007, by leonardo maffi.

def mode_finder(seq, verbose=False):
    """mode_finder(data, verbose=False): return the most frequent element of
    an iterable seq (the mode). This algorithm works only if freq(mode) > ndata/2
    """
    seq = iter(seq)
    candidate = seq.next()
    count = 1
    if verbose:
        print "Inside mode_finder, verbose=True:"
        print (candidate, count),
    for el in seq: # The first one is already used
        if el == candidate:
            count += 1
        else:
            count -= 1
            if count == 0:
                candidate = el
                count = 1
        if verbose:
            print (candidate, count),
    if verbose:
        print
        print "Mode:", candidate
        print "count:", count
        print "End of mode_finder."
    return candidate


if __name__ == "__main__":
    from random import choice, shuffle, seed

    def gen_data(ndata=20, verbose=False):
        values = "abcdefgh"
        data = [values[0]] * (ndata // 2 + 1)
        if verbose: print data, "\n"
        data += [choice(values[1:]) for _ in xrange(ndata-len(data))]
        if verbose: print data, "\n"
        shuffle(data)
        return "".join(data)

    seed(2)
    data = gen_data(verbose=True)
    print "data:", data, "\n"
    m = mode_finder(data, verbose=True)