(PHP 3>= 3.0.17, PHP 4 >= 4.0.1, PHP 5)
levenshtein --
Calculate Levenshtein distance between two strings
Description
int
levenshtein ( string str1, string str2 [, int cost_ins [, int cost_rep, int cost_del]])
This function returns the Levenshtein-Distance between the
two argument strings or -1, if one of the argument strings
is longer than the limit of 255 characters (255 should be
more than enough for name or dictionary comparison, and
nobody serious would be doing genetic analysis with PHP).
The Levenshtein distance is defined as the minimal number of
characters you have to replace, insert or delete to transform
str1 into str2.
The complexity of the algorithm is O(m*n),
where n and m are the
length of str1 and
str2 (rather good when compared to
similar_text(), which is O(max(n,m)**3),
but still expensive).
In its simplest form the function will take only the two
strings as parameter and will calculate just the number of
insert, replace and delete operations needed to transform
str1 into str2.
A second variant will take three additional parameters that
define the cost of insert, replace and delete operations. This
is more general and adaptive than variant one, but not as
efficient.
See also soundex(),
similar_text(), and
metaphone().
