Calculate the Hamming distance between two equal-length strings.
npm install @stdlib/string-base-distances-hammingWe believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js. The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases. When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there. To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
About stdlib...
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Calculate the [Hamming distance][hamming-distance] between two equal-length strings.
``bash`
npm install @stdlib/string-base-distances-hamming
`javascript`
var hammingDistance = require( '@stdlib/string-base-distances-hamming' );
#### hammingDistance( s1, s2 )
Calculates the [Hamming distance][hamming-distance] between two equal-length strings.
`javascript
var dist = hammingDistance( 'frog', 'from' );
// returns 1
dist = hammingDistance( 'tooth', 'froth' );
// returns 2
dist = hammingDistance( 'cat', 'cot' );
// returns 1
dist = hammingDistance( '', '' );
// returns 0
dist = hammingDistance( '1638452297', '2311638451' );
// returns 10
`
- If the two strings differ in length, the [Hamming distance][hamming-distance] is not defined. Consequently, when provided two input strings of unequal length, the function returns a sentinel value of -1.
- As the function calculates the [Hamming distance][hamming-distance] by comparing UTF-16 code units, the function should behave as expected for strings composed of most characters. However, the function is likely to not behave as expected if strings contain visual characters composed of multiple Unicode code points, such as certain mathematical symbols and grapheme clusters (e.g., emojis).
`javascript
var hammingDistance = require( '@stdlib/string-base-distances-hamming' );
var dist = hammingDistance( 'algorithms', 'altruistic' );
// returns 7
dist = hammingDistance( 'elephant', 'Tashkent' );
// returns 6
dist = hammingDistance( 'javascript', 'typescript' );
// returns 4
dist = hammingDistance( 'hamming', 'ladybug' );
// returns 5
`
*
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
See [LICENSE][stdlib-license].
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/string-base-distances-hamming.svg
[npm-url]: https://npmjs.org/package/@stdlib/string-base-distances-hamming
[test-image]: https://github.com/stdlib-js/string-base-distances-hamming/actions/workflows/test.yml/badge.svg?branch=v0.2.3
[test-url]: https://github.com/stdlib-js/string-base-distances-hamming/actions/workflows/test.yml?query=branch:v0.2.3
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/string-base-distances-hamming/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/string-base-distances-hamming?branch=main
[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg
[chat-url]: https://stdlib.zulipchat.com
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/string-base-distances-hamming/tree/deno
[deno-readme]: https://github.com/stdlib-js/string-base-distances-hamming/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/string-base-distances-hamming/tree/umd
[umd-readme]: https://github.com/stdlib-js/string-base-distances-hamming/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/string-base-distances-hamming/tree/esm
[esm-readme]: https://github.com/stdlib-js/string-base-distances-hamming/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/string-base-distances-hamming/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/string-base-distances-hamming/main/LICENSE
[hamming-distance]: https://en.wikipedia.org/wiki/Hamming_distance