https://github.com/stdlib-js/array-base-at2d
Return an element from a two-dimensional nested array.
https://github.com/stdlib-js/array-base-at2d
2d access accessor array at base get getter javascript matrix multidimensional ndarray node node-js nodejs retrieve stdlib
Last synced: 6 months ago
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Return an element from a two-dimensional nested array.
- Host: GitHub
- URL: https://github.com/stdlib-js/array-base-at2d
- Owner: stdlib-js
- License: apache-2.0
- Created: 2024-01-21T00:33:25.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2025-03-31T01:08:46.000Z (6 months ago)
- Last Synced: 2025-04-12T20:47:27.465Z (6 months ago)
- Topics: 2d, access, accessor, array, at, base, get, getter, javascript, matrix, multidimensional, ndarray, node, node-js, nodejs, retrieve, stdlib
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 203 KB
- Stars: 1
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
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README
About stdlib...
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# at2d
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Return an element from a two-dimensional nested array.
## Installation
```bash
npm install @stdlib/array-base-at2d
```
Alternatively,
- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).
The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
## Usage
```javascript
var at2d = require( '@stdlib/array-base-at2d' );
```
#### at2d( x, i0, i1 )
Returns an element from a two-dimensional nested array.
```javascript
var x = [ [ 1, 2 ], [ 3, 4 ] ];
var out = at2d( x, 0, 1 );
// returns 2
out = at2d( x, 1, 0 );
// returns 3
```
The function accepts the following arguments:
- **x**: two-dimensional nested input array.
- **i0**: first dimension index.
- **i1**: second dimension index.
## Notes
- Negative indices are resolved relative to the last element along the respective dimension, with the last element corresponding to `-1`.
- If provided out-of-bounds indices, the function always returns `undefined`.
## Examples
```javascript
var papply = require( '@stdlib/utils-papply' );
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' ).factory;
var filled2dBy = require( '@stdlib/array-base-filled2d-by' );
var binary2d = require( '@stdlib/array-base-binary2d' );
var zeros2d = require( '@stdlib/array-base-zeros2d' );
var at2d = require( '@stdlib/array-base-at2d' );
var shape = [ 3, 3 ];
// Define a nested input array:
var x = filled2dBy( shape, discreteUniform( -100, 100 ) );
console.log( x );
// Define arrays containing random index values:
var i0 = filled2dBy( shape, discreteUniform( -shape[0], shape[0]-1 ) );
console.log( i0 );
var i1 = filled2dBy( shape, discreteUniform( -shape[1], shape[1]-1 ) );
console.log( i1 );
// Define an output array:
var out = zeros2d( shape );
console.log( out );
// Fill the output array with randomly selected values from the input array:
binary2d( [ i0, i1, out ], shape, papply( at2d, x ) );
console.log( out );
```
* * *
## 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 © 2016-2025. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/array-base-at2d.svg
[npm-url]: https://npmjs.org/package/@stdlib/array-base-at2d
[test-image]: https://github.com/stdlib-js/array-base-at2d/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/array-base-at2d/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/array-base-at2d/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/array-base-at2d?branch=main
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im
[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/array-base-at2d/tree/deno
[deno-readme]: https://github.com/stdlib-js/array-base-at2d/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/array-base-at2d/tree/umd
[umd-readme]: https://github.com/stdlib-js/array-base-at2d/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/array-base-at2d/tree/esm
[esm-readme]: https://github.com/stdlib-js/array-base-at2d/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/array-base-at2d/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/array-base-at2d/main/LICENSE