npm package: @stdlib/random-shuffle
Description: Shuffle elements of an array-like object.
Author: The Stdlib Authors
Latest version: 0.2.3

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  <summary>
    About stdlib...
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</details>

# Shuffle

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

> Shuffle elements of an array-like object.

<section class="intro">

</section>

<!-- /.intro -->

<section class="installation">

## Installation

```bash
npm install @stdlib/random-shuffle
```

</section>

<section class="usage">

## Usage

```javascript
var shuffle = require( '@stdlib/random-shuffle' );
```

#### shuffle( arr\[, options] )

Shuffles elements of an array-like object.

```javascript
var arr = [ 1, 2, 3 ];
var out = shuffle( arr );
// e.g., returns [ 3, 1, 2 ]
```

The function accepts the following `options`:

-   **copy**: `string` indicating whether to return a copy (`deep`,`shallow` or `none`). Default: `shallow`.

By default, the function returns a shallow copy. To mutate the input `array` (e.g., when input values can be discarded or when optimizing memory usage), set `copy` to `none`.

```javascript
var arr = [ 1, 2, 3 ];
var out = shuffle( arr, {
    'copy': 'none'
});
var bool = ( arr === out );
// returns true
```

To return a deep copy, set the `copy` option to `deep`.

```javascript
var obj = {
    'beep': 'boop'
};
var arr = [ [ obj ], [ obj ], [ obj ] ];

// Deep copy:
var out = shuffle( arr, {
    'copy': 'deep'
});
var bool = ( arr === out );
// returns false

bool = ( arr[2] === out[2] );
// returns false

// Shallow copy:
out = shuffle( arr, {
    'copy': 'shallow'
});
bool = ( arr === out );
// returns false

bool = ( arr[2] === out[2] );
// returns true
```

#### shuffle.factory( \[options] )

Returns a `function` to shuffle elements of `array`-like objects.

```javascript
var myshuffle = shuffle.factory();
```

The function accepts the following `options`:

-   **copy**: `string` specifying the default copy option (`deep`,`shallow` or `none`). Default: `shallow`.
-   **seed**: pseudorandom number generator seed.

To seed the underlying pseudorandom number generator, set the `seed` option.

```javascript
var myshuffle = shuffle.factory({
    'seed': 239
});

var out = myshuffle( [ 0, 1, 2, 3, 4 ] );
// e.g., returns [ 3, 4, 1, 0, 2 ]
```

By default, the returned functions create shallow copies when shuffling. To override the default `copy` strategy, set the `copy` option.

```javascript
var myshuffle = shuffle.factory({
    'copy': 'none',
    'seed': 867
});

// Created shuffle function mutates input array by default:
var arr = [ 1, 2, 3, 4, 5, 6 ];
var out = myshuffle( arr );
var bool = ( arr === out );
// returns true

// Default option can be overridden:
arr = [ 1, 2, 3, 4 ];
out = myshuffle( arr, {
    'copy': 'shallow'
});
bool = ( arr === out );
// returns false
```

</section>

<!-- /.usage -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var shuffle = require( '@stdlib/random-shuffle' );

var result;
var data;
var i;

data = new Array( 20 );
for ( i = 0; i < data.length; i++ ) {
    data[ i ] = i;
}

for ( i = 0; i < 10; i++ ) {
    result = shuffle( data );
    console.log( result );
}
```

</section>

<!-- /.examples -->

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

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/random-sample`][@stdlib/random/sample]</span><span class="delimiter">: </span><span class="description">sample elements from an array-like object.</span>

</section>

<!-- /.related -->

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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].

</section>

<!-- /.stdlib -->

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[npm-url]: https://npmjs.org/package/@stdlib/random-shuffle

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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/random-shuffle/tree/deno
[deno-readme]: https://github.com/stdlib-js/random-shuffle/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/random-shuffle/tree/umd
[umd-readme]: https://github.com/stdlib-js/random-shuffle/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/random-shuffle/tree/esm
[esm-readme]: https://github.com/stdlib-js/random-shuffle/blob/esm/README.md
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/random-shuffle/main/LICENSE

<!-- <related-links> -->

[@stdlib/random/sample]: https://www.npmjs.com/package/@stdlib/random-sample

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</section>

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