npm package: @stdlib/string-base-distances-hamming
Description: Calculate the Hamming distance between two equal-length strings.
Author: The Stdlib Authors
Latest version: 0.2.3

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# hammingDistance

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> Calculate the [Hamming distance][hamming-distance] between two equal-length strings.

<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/string-base-distances-hamming
```

</section>

<section class="usage">

## Usage

```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
```

</section>

<!-- /.usage -->

<!-- Package notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

## Notes

-   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).

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

```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
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

</section>

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<section class="main-repo" >

* * *

## Notice

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]

---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

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[stdlib]: https://github.com/stdlib-js/stdlib

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[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
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/string-base-distances-hamming/main/LICENSE

[hamming-distance]: https://en.wikipedia.org/wiki/Hamming_distance

</section>

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