https://github.com/stdlib-js/ndarray-slice-dimension
Return a read-only view of an input ndarray when sliced along a specified dimension.
https://github.com/stdlib-js/ndarray-slice-dimension
copy data javascript matrix ndarray node node-js nodejs select slice stdlib structure types vector view
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Return a read-only view of an input ndarray when sliced along a specified dimension.
- Host: GitHub
- URL: https://github.com/stdlib-js/ndarray-slice-dimension
- Owner: stdlib-js
- License: apache-2.0
- Created: 2023-10-13T03:15:42.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2026-02-09T04:26:11.000Z (5 months ago)
- Last Synced: 2026-02-21T08:39:38.403Z (4 months ago)
- Topics: copy, data, javascript, matrix, ndarray, node, node-js, nodejs, select, slice, stdlib, structure, types, vector, view
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 2.45 MB
- Stars: 1
- Watchers: 2
- 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
- Notice: NOTICE
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README
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# sliceDimension
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Return a read-only view of an input [`ndarray`][@stdlib/ndarray/ctor] when sliced along a specified dimension.
## Installation
```bash
npm install @stdlib/ndarray-slice-dimension
```
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 sliceDimension = require( '@stdlib/ndarray-slice-dimension' );
```
#### sliceDimension( x, dim, slice\[, options] )
Returns a **read-only** view of an input [`ndarray`][@stdlib/ndarray/ctor] when sliced along a specified dimension.
```javascript
var Slice = require( '@stdlib/slice-ctor' );
var ndarray = require( '@stdlib/ndarray-ctor' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var buffer = [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ];
var shape = [ 3, 2 ];
var strides = [ 2, 1 ];
var offset = 0;
var x = ndarray( 'generic', buffer, shape, strides, offset, 'row-major' );
// returns
var sh = x.shape;
// returns [ 3, 2 ]
var arr = ndarray2array( x );
// returns [ [ 1.0, 2.0 ], [ 3.0, 4.0 ], [ 5.0, 6.0 ] ]
var s = new Slice( null, null, -1 );
// returns
var y = sliceDimension( x, 0, s );
// returns
sh = y.shape;
// returns [ 3, 2 ]
arr = ndarray2array( y );
// returns [ [ 5.0, 6.0 ], [ 3.0, 4.0 ], [ 1.0, 2.0 ] ]
```
The function accepts the following arguments:
- **x**: input [`ndarray`][@stdlib/ndarray/ctor].
- **dim**: index of dimension along which to slice. If provided an integer less than zero, the dimension index is resolved relative to the last dimension, with the last dimension corresponding to the value `-1`.
- **slice**: a [`Slice`][@stdlib/slice/ctor] instance, `null`, `undefined`, or an integer. If provided `null` or `undefined`, the argument is equivalent to `new Slice()` (i.e., the returned view should include all elements along a specified dimension). If provided an integer less than zero, the corresponding element along the specified dimension is resolved relative to the last element along that dimension. For negative integers, the last element corresponds to the value `-1`.
- **options**: function options.
The function supports the following `options`:
- **strict**: boolean indicating whether to enforce strict bounds checking.
By default, the function throws an error when provided a slice which exceeds array bounds. To return an empty array when a slice exceeds array bounds, set the `strict` option to `false`.
```javascript
var Slice = require( '@stdlib/slice-ctor' );
var ndarray = require( '@stdlib/ndarray-ctor' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var buffer = [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ];
var shape = [ 3, 2 ];
var strides = [ 2, 1 ];
var offset = 0;
var x = ndarray( 'generic', buffer, shape, strides, offset, 'row-major' );
// returns
var sh = x.shape;
// returns [ 3, 2 ]
var arr = ndarray2array( x );
// returns [ [ 1.0, 2.0 ], [ 3.0, 4.0 ], [ 5.0, 6.0 ] ]
var s = new Slice( 10, 20, 2 );
// returns
var y = sliceDimension( x, 1, s, {
'strict': false
});
// returns
sh = y.shape;
// returns [ 3, 0 ]
arr = ndarray2array( y );
// returns []
```
## Examples
```javascript
var S = require( '@stdlib/slice-ctor' );
var array = require( '@stdlib/ndarray-array' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var zeroTo = require( '@stdlib/array-base-zero-to' );
var sliceDimension = require( '@stdlib/ndarray-slice-dimension' );
// Alias `null` to allow for more compact indexing expressions:
var _ = null;
// Create a linear ndarray buffer:
var buf = zeroTo( 27 );
// Create an ndarray:
var x = array( buf, {
'shape': [ 3, 3, 3 ]
});
// Get each matrix...
var y1 = sliceDimension( x, 0, 0 );
// returns
var a1 = ndarray2array( y1 );
// returns [ [ 0, 1, 2 ], [ 3, 4, 5 ], [ 6, 7, 8 ] ]
var y2 = sliceDimension( x, 0, 1 );
// returns
var a2 = ndarray2array( y2 );
// returns [ [ 9, 10, 11 ], [ 12, 13, 14 ], [ 15, 16, 17 ] ]
var y3 = sliceDimension( x, 0, 2 );
// returns
var a3 = ndarray2array( y3 );
// returns [ [ 18, 19, 20 ], [ 21, 22, 23 ], [ 24, 25, 26 ] ]
// Reverse the matrix order:
var s = S( _, _, -1 );
var y4 = sliceDimension( x, 0, s );
// returns
var a4 = ndarray2array( y4 );
// returns [...]
// Get the second rows from each matrix:
var y5 = sliceDimension( x, 1, 1 );
// returns
var a5 = ndarray2array( y5 );
// returns [ [ 3, 4, 5 ], [ 12, 13, 14 ], [ 21, 22, 23 ] ]
// Get the second columns from each matrix:
var y6 = sliceDimension( x, 2, 1 );
// returns
var a6 = ndarray2array( y6 );
// returns [ [ 1, 4, 7 ], [ 10, 13, 16 ], [ 19, 22, 25 ] ]
```
* * *
## See Also
- [`@stdlib/ndarray-array`][@stdlib/ndarray/array]: multidimensional arrays.
- [`@stdlib/ndarray-ctor`][@stdlib/ndarray/ctor]: multidimensional array constructor.
- [`@stdlib/ndarray-slice`][@stdlib/ndarray/slice]: return a read-only view of an input ndarray.
- [`@stdlib/ndarray-slice-dimension-from`][@stdlib/ndarray/slice-dimension-from]: return a read-only shifted view of an input ndarray along a specific dimension.
- [`@stdlib/ndarray-slice-dimension-to`][@stdlib/ndarray/slice-dimension-to]: return a read-only truncated view of an input ndarray along a specific dimension.
* * *
## 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 © 2016-2026. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/ndarray-slice-dimension.svg
[npm-url]: https://npmjs.org/package/@stdlib/ndarray-slice-dimension
[test-image]: https://github.com/stdlib-js/ndarray-slice-dimension/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/ndarray-slice-dimension/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/ndarray-slice-dimension/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/ndarray-slice-dimension?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/ndarray-slice-dimension/tree/deno
[deno-readme]: https://github.com/stdlib-js/ndarray-slice-dimension/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/ndarray-slice-dimension/tree/umd
[umd-readme]: https://github.com/stdlib-js/ndarray-slice-dimension/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/ndarray-slice-dimension/tree/esm
[esm-readme]: https://github.com/stdlib-js/ndarray-slice-dimension/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/ndarray-slice-dimension/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/ndarray-slice-dimension/main/LICENSE
[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/ndarray-ctor
[@stdlib/slice/ctor]: https://github.com/stdlib-js/slice-ctor
[@stdlib/ndarray/array]: https://github.com/stdlib-js/ndarray-array
[@stdlib/ndarray/slice]: https://github.com/stdlib-js/ndarray-slice
[@stdlib/ndarray/slice-dimension-from]: https://github.com/stdlib-js/ndarray-slice-dimension-from
[@stdlib/ndarray/slice-dimension-to]: https://github.com/stdlib-js/ndarray-slice-dimension-to