(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)
levenshtein — Calculate Levenshtein distance between two strings
$string1
,$string2
,$insertion_cost
= 1,$replacement_cost
= 1,$deletion_cost
= 1 The Levenshtein distance is defined as the minimal number of characters you have to replace, insert or delete to transform string1
into string2
. The complexity of the algorithm is O(m*n)
, where n
and m
are the length of string1
and string2
(rather good when compared to similar_text(), which is O(max(n,m)**3)
, but still expensive).
If insertion_cost
, replacement_cost
and/or deletion_cost
are unequal to 1
, the algorithm adapts to choose the cheapest transforms. E.g. if $insertion_cost + $deletion_cost < $replacement_cost
, no replacements will be done, but rather inserts and deletions instead.
string1
One of the strings being evaluated for Levenshtein distance.
string2
One of the strings being evaluated for Levenshtein distance.
insertion_cost
Defines the cost of insertion.
replacement_cost
Defines the cost of replacement.
deletion_cost
Defines the cost of deletion.
This function returns the Levenshtein-Distance between the two argument strings.
Version | Description |
---|---|
8.0.0 | Prior to this version, levenshtein() had to be called with either two or five arguments. |
8.0.0 | Prior to this version, levenshtein() would return -1 if one of the argument strings is longer than 255 characters. |
Example #1 levenshtein() example
<?php
// input misspelled word
$input = 'carrrot';
// array of words to check against
$words = array('apple','pineapple','banana','orange',
'radish','carrot','pea','bean','potato');
// no shortest distance found, yet
$shortest = -1;
// loop through words to find the closest
foreach ($words as $word) {
// calculate the distance between the input word,
The above example will output:
Input word: carrrot Did you mean: carrot?