Revision as of 16:53, 13 January 2015

levenshteinDistance is a string comparison function. The metric was developed by Vladimir Levenshtein in 1965. The function tracks the difference between two strings based on single-character changes. In other words, the number of insertions, deletions, and substitutions required to change the first string into the second. This metric is useful for deciding what strings are "close" to being the same, such as finding a partial match against a player or character name.

The levenshteinDistance function is added to String.prototype, meaning it can be treated as a function of string objects.

Original JavaScript implementation from wikibooks.org.

Syntax

str.levenshteinDistance(otherStr)

Parameters

otherStr

The string to compare against str.

Return Value

levenshteinDistance returns an integer of the total number of insertions, deletions, and substitutions required to change str into otherStr.

Example

The distance between "kitten" and "sitting" is 3:

1. kitten → sitten (substitute "s" for "k")
2. sitten → sittin (substitute "i" for "e")
3. sittin → sitting (insert "g")

on('chat:message', function(msg) {
    var params = msg.content.splitArgs(),
        command = params.shift().substring(1).toLowerCase(),
        characterName = params[0],
        potentialCharacters, foundCharacter;

    if (msg.type === 'api' && command === 'echocharacter') {
        potentialCharacters = filterObjs(function(obj) { return obj.get('type') === 'character' && obj.get('name').indexOf(who) >= 0; });
        foundCharacter = _.sortBy(potentialCharacters, function(chr) {
            return chr.get('name').toLowerCase().levenshteinDistance(who.toLowerCase());
        })[0];

        if (foundCharacter) {
            sendChat('System', characterName + ' interpreted as ' + foundCharacter.get('name'));
        } else {
            sendChat('System', 'Could not find character for ' + characterName);
        }
    }
});