https://github.com/stdlib-js/ndarray-slice-dimension-from
Return a read-only shifted view of an input ndarray along a specific dimension.
https://github.com/stdlib-js/ndarray-slice-dimension-from
copy data javascript matrix ndarray node node-js nodejs shift slice stdlib structure truncate types vector view
Last synced: 10 months ago
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Return a read-only shifted view of an input ndarray along a specific dimension.
- Host: GitHub
- URL: https://github.com/stdlib-js/ndarray-slice-dimension-from
- Owner: stdlib-js
- License: apache-2.0
- Created: 2023-10-21T01:08:19.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2025-03-17T02:31:56.000Z (11 months ago)
- Last Synced: 2025-04-13T00:03:23.505Z (10 months ago)
- Topics: copy, data, javascript, matrix, ndarray, node, node-js, nodejs, shift, slice, stdlib, structure, truncate, types, vector, view
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 1.76 MB
- 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
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# sliceDimensionFrom
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Return a read-only shifted view of an input [`ndarray`][@stdlib/ndarray/ctor] along a specified dimension.
## Installation
```bash
npm install @stdlib/ndarray-slice-dimension-from
```
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 sliceDimensionFrom = require( '@stdlib/ndarray-slice-dimension-from' );
```
#### sliceDimensionFrom( x, dim, start\[, options] )
Returns a **read-only** shifted view of an input [`ndarray`][@stdlib/ndarray/ctor] along a specified dimension.
```javascript
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 y = sliceDimensionFrom( x, 0, 1 );
// returns
sh = y.shape;
// returns [ 2, 2 ]
arr = ndarray2array( y );
// returns [ [ 3.0, 4.0 ], [ 5.0, 6.0 ] ]
```
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`.
- **start**: starting index (inclusive). 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 starting index which exceeds array bounds. To return an empty array when a starting index exceeds array bounds, set the `strict` option to `false`.
```javascript
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 y = sliceDimensionFrom( x, 1, 20, {
'strict': false
});
// returns
sh = y.shape;
// returns [ 3, 0 ]
arr = ndarray2array( y );
// returns []
```
## Examples
```javascript
var array = require( '@stdlib/ndarray-array' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var zeroTo = require( '@stdlib/array-base-zero-to' );
var sliceDimensionFrom = require( '@stdlib/ndarray-slice-dimension-from' );
// Create a linear ndarray buffer:
var buf = zeroTo( 27 );
// Create an ndarray:
var x = array( buf, {
'shape': [ 3, 3, 3 ]
});
// Get the last two rows of each matrix:
var y1 = sliceDimensionFrom( x, 1, 1 );
// returns
var a1 = ndarray2array( y1 );
// returns [ [ [ 3, 4, 5 ], [ 6, 7, 8 ] ], [ [ 12, 13, 14 ], [ 15, 16, 17 ] ], [ [ 21, 22, 23 ], [ 24, 25, 26 ] ] ]
// Get the last columns of each matrix:
var y2 = sliceDimensionFrom( x, 2, 1 );
// returns
var a2 = ndarray2array( y2 );
// returns [ [ [ 1, 2 ], [ 4, 5 ], [ 7, 8 ] ], [ [ 10, 11 ], [ 13, 14 ], [ 16, 17 ] ], [ [ 19, 20 ], [ 22, 23 ], [ 25, 26 ] ] ]
// Get the last two matrices:
var y3 = sliceDimensionFrom( x, 0, 1 );
// returns
var a3 = ndarray2array( y3 );
// returns [ [ [ 9, 10, 11 ], [ 12, 13, 14 ], [ 15, 16, 17 ] ], [ [ 18, 19, 20 ], [ 21, 22, 23 ], [ 24, 25, 26 ] ] ]
```
* * *
## 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`][@stdlib/ndarray/slice-dimension]: return a read-only view of an input ndarray when sliced along a specified 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.
- [`@stdlib/ndarray-slice-from`][@stdlib/ndarray/slice-from]: return a read-only shifted view of an input ndarray.
* * *
## 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/ndarray-slice-dimension-from.svg
[npm-url]: https://npmjs.org/package/@stdlib/ndarray-slice-dimension-from
[test-image]: https://github.com/stdlib-js/ndarray-slice-dimension-from/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/ndarray-slice-dimension-from/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/ndarray-slice-dimension-from/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/ndarray-slice-dimension-from?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/ndarray-slice-dimension-from/tree/deno
[deno-readme]: https://github.com/stdlib-js/ndarray-slice-dimension-from/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/ndarray-slice-dimension-from/tree/umd
[umd-readme]: https://github.com/stdlib-js/ndarray-slice-dimension-from/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/ndarray-slice-dimension-from/tree/esm
[esm-readme]: https://github.com/stdlib-js/ndarray-slice-dimension-from/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/ndarray-slice-dimension-from/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/ndarray-slice-dimension-from/main/LICENSE
[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/ndarray-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]: https://github.com/stdlib-js/ndarray-slice-dimension
[@stdlib/ndarray/slice-dimension-to]: https://github.com/stdlib-js/ndarray-slice-dimension-to
[@stdlib/ndarray/slice-from]: https://github.com/stdlib-js/ndarray-slice-from