Levenshtein distance in Python for lists of objects comparable with the `!=` operator. Uses the Wagner-Fischer algorithm.

levenshtein.py

import numpy as np


def levenshtein(l1, l2):
    """ Computes Levenshtein distance between two list-like objects
        Args:
            l1, l2: subscriptable objects compatible with len()
                containing objects comparable with the `!=` operator.
    """
    # initializing the distance matrix
    m = np.zeros(shape=(len(l1), len(l2)))
    m[0, :] = range(0, len(l2))
    m[:, 0] = range(0, len(l1))
    
    for i in range(1, len(l1)):
        for j in range(1, len(l2)):
            cost = 0
            if l1[i] != l2[j]:
                cost = 1
            # distance at i,j is the minimal distance
            # of the previous steps + current cost
            m[i, j] = min(m[i - 1, j], m[i, j - 1], m[i - 1, j - 1]) + cost
    return m[len(l1) - 1, len(l2) - 1]

This code is released under the .