def levenshteinDistance(str1, str2):
    m = len(str1)
    n = len(str2)
    lensum = float(m + n)
    d = []
    for i in range(m+1):
        d.append([i])
    del d[0][0]
    for j in range(n+1):
        d[0].append(j)
    for j in range(1,n+1):
        for i in range(1,m+1):
            if str1[i-1] == str2[j-1]:
                d[i].insert(j,d[i-1][j-1])
            else:
                minimum = min(d[i-1][j]+1, d[i][j-1]+1, d[i-1][j-1]+2)
                d[i].insert(j, minimum)
    ldist = d[-1][-1]
    ratio = (lensum - ldist)/lensum
    return {'distance':ldist, 'ratio':ratio}

print(levenshteinDistance("kitten","sitting"))
print(levenshteinDistance("rosettacode","raisethysword"))