Levenshtein distance with bound/limit

Question

I have found some Python implementations of the Levenshtein distance.

I am wondering though how these algorithms can be efficiently modified so that the

Answer 1

As described in Levenstein distance limit, you can add a test over the row that is computed to return early:

def levenshtein(s1, s2, maximum):
    if len(s1) > len(s2):
        s1, s2 = s2, s1

    distances = range(len(s1) + 1)
    for i2, c2 in enumerate(s2):
        distances_ = [i2+1]
        for i1, c1 in enumerate(s1):
            if c1 == c2:
                distances_.append(distances[i1])
            else:
                distances_.append(1 + min((distances[i1], distances[i1 + 1], distances_[-1])))
        if all((x >= maximum for x in distances_)):
            return False
        distances = distances_
    return distances[-1]