npm package: @stdlib/array-base-at
Description: Return an element from an array.
Author: The Stdlib Authors
Latest version: 0.2.3

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  <summary>
    About stdlib...
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  <p>We 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.</p>
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# at

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> Return an element from an array.

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/array-base-at
```

</section>

<section class="usage">

## Usage

```javascript
var at = require( '@stdlib/array-base-at' );
```

#### at( x, index )

Returns an element from an array.

```javascript
var x = [ 1, 2, 3, 4 ];

var out = at( x, 0 );
// returns 1

out = at( x, 1 );
// returns 2

out = at( x, -2 );
// returns 3
```

The function accepts the following arguments:

-   **x**: an input array.
-   **index**: element index.

</section>

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

<section class="notes">

## Notes

-   If provided an array-like object having an `at` method, the function defers execution to that method and assumes that the method has the following signature:

    ```text
    x.at( index )
    ```

    If provided an array-like object without an `at` method, the function normalizes a provided index and returns a specified element.

-   Negative indices are resolved relative to the last array element, with the last element corresponding to `-1`.

-   If provided out-of-bounds indices, the function always returns `undefined`.

</section>

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<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var at = require( '@stdlib/array-base-at' );

// Define an array:
var x = discreteUniform( 10, -100, 100 );

// Define an array containing random index values:
var indices = discreteUniform( 100, -x.length, x.length-1 );

// Randomly selected values from the input array:
var i;
for ( i = 0; i < indices.length; i++ ) {
    console.log( 'x[%d] = %d', indices[ i ], at( x, indices[ i ] ) );
}
```

</section>

<!-- /.examples -->

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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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[npm-url]: https://npmjs.org/package/@stdlib/array-base-at

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[test-url]: https://github.com/stdlib-js/array-base-at/actions/workflows/test.yml?query=branch:v0.2.3

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/array-base-at/main.svg
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[umd]: https://github.com/umdjs/umd
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