Fuzzy string matching?

[Magnus L. Hetland]

Yet another version, without the append...

def distance(a,b):
    "Calculates the Levenshtein distance between a and b."
    n, m = len(a), len(b)
    if n > m:
        # Make sure n <= m, to use O(min(n,m)) space
        a,b = b,a
        n,m = m,n
        
    current = range(n+1)
    for i in range(1,m+1):
        previous, current = current, [i]+[0]*m
        for j in range(1,n+1):
            add, delete = previous[j]+1, current[j-1]+1
            change = previous[j-1]
            if a[j-1] != b[i-1]:
                change = change + 1
            current[j] = min(add, delete, change)
            
    return current[n]


I *could* have written [i]*(m+1) - but I thought this was clearer... :)

--

  Magnus              Making no sound / Yet smouldering with passion
  Lie          The firefly is still sadder / Than the moaning insect
  Hetland                                       : Minamoto Shigeyuki