https://github.com/franciscohanna92/levenshtein-distance

Levenshtein Distance string comparator
https://github.com/franciscohanna92/levenshtein-distance

Last synced: 7 days ago
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Levenshtein Distance string comparator

• Host: GitHub
• URL: https://github.com/franciscohanna92/levenshtein-distance
• Owner: franciscohanna92
• Created: 2018-09-16T00:37:25.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2018-09-16T00:52:20.000Z (over 6 years ago)
• Last Synced: 2024-11-09T13:38:37.386Z (2 months ago)
• Language: JavaScript
• Size: 4.88 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Levenshtein Distance string comparator

[**Try it out**](http://franciscohanna.me/levenshtein-distance/)

From Wikipedia:

> In information theory, linguistics and computer science, the Levenshtein distance is a string metric for measuring the difference between two sequences. Informally, the Levenshtein distance between two words is the minimum number of single-character edits (insertions, deletions or substitutions) required to change one word into the other.

You can read about this algorithm in the [Wikipedia page](https://en.wikipedia.org/wiki/Levenshtein_distance)

The implementaion used in this little project, wich you can find in `main.js`, is the following:

```javascript

/**

 * Compares two strings with the matrix variant of the Levenshtein Distance algorithm

 * @param {string} string1 First string for comparisson

 * @param {string} string2 Second string for comparisson

 * @return {number} The Lev. Distance between string1 and string2

 */

function levenshtein(string1, string2) {

    var length1 = string1.length;

    var length2 = string2.length;

    var matrix = [];

    var cost = 0;

    var a = 0;

    if (length1 == 0) {

        return length2;

    }

    if (length2 == 0) {

        return length1;

    }

    var matrix = new ArrayBuffer((length1 + 1) * (length2 + 1));

    a = length1 + 1;

    // Populate matrix with initial data

    for (var i = 0; i <= length1; matrix[i] = i++);

    for (var j = 0; j <= length2; matrix[j * a] = j++);

    for (var i = 1; i <= length1; i++) {

        for (var j = 1; j <= length2; j++) {

            if (string1[i - 1] == string2[j - 1])

                cost = 0;

            else

                cost = 2; // The cost is two if a substitution is nedeed

            var r = matrix[j * a + i - 1] + 1;

            var s = matrix[(j - 1) * a + i] + 1;

            var t = matrix[(j - 1) * a + i - 1] + cost;

            matrix[j * a + i] = Math.min(Math.min(r, s), t);

        }

    }

    return (matrix[length2 * a + length1]);

}

```