https://github.com/stdlib-js/slice-base-length
Compute the number of elements in a normalized slice.
https://github.com/stdlib-js/slice-base-length
base canonical javascript len length ndarray node node-js nodejs normalized numel range reduced sequence shape slice stdlib subseq subsequence
Last synced: 4 months ago
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Compute the number of elements in a normalized slice.
- Host: GitHub
- URL: https://github.com/stdlib-js/slice-base-length
- Owner: stdlib-js
- License: apache-2.0
- Created: 2023-09-21T12:44:46.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2024-12-29T03:29:22.000Z (5 months ago)
- Last Synced: 2024-12-29T04:19:56.362Z (5 months ago)
- Topics: base, canonical, javascript, len, length, ndarray, node, node-js, nodejs, normalized, numel, range, reduced, sequence, shape, slice, stdlib, subseq, subsequence
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 208 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
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# sliceLength
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Compute the number of elements in a [normalized slice][@stdlib/slice/base/normalize-slice].
## Installation
```bash
npm install @stdlib/slice-base-length
```
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 sliceLength = require( '@stdlib/slice-base-length' );
```
#### sliceLength( slice )
Returns the number of elements in a [normalized slice][@stdlib/slice/base/normalize-slice].
```javascript
var Slice = require( '@stdlib/slice-ctor' );
var normalizeSlice = require( '@stdlib/slice-base-normalize-slice' );
var s = normalizeSlice( new Slice( -3, null, -1 ), 10, false );
// returns
var len = sliceLength( s );
// returns 8
```
## Examples
```javascript
var Slice = require( '@stdlib/slice-ctor' );
var normalizeSlice = require( '@stdlib/slice-base-normalize-slice' );
var incrspace = require( '@stdlib/array-base-incrspace' );
var sliceLength = require( '@stdlib/slice-base-length' );
var s1 = new Slice( 2, null, -1 );
var s2 = normalizeSlice( s1, 10, false );
var v = sliceLength( s2 );
console.log( '%s => %s => %d', s1.toString(), s2.toString(), v );
console.log( '[ %s ]', incrspace( s2.start, s2.stop || -1, s2.step ).join( ', ' ) );
// => '[ 2, 1, 0 ]'
s1 = new Slice( null, null, -3 );
s2 = normalizeSlice( s1, 10, false );
v = sliceLength( s2 );
console.log( '%s => %s => %d', s1.toString(), s2.toString(), v );
console.log( '[ %s ]', incrspace( s2.start, s2.stop || -1, s2.step ).join( ', ' ) );
// => '[ 9, 6, 3, 0 ]'
s1 = new Slice( null, 8, 3 );
s2 = normalizeSlice( s1, 10, false );
v = sliceLength( s2 );
console.log( '%s => %s => %d', s1.toString(), s2.toString(), v );
console.log( '[ %s ]', incrspace( s2.start, s2.stop || -1, s2.step ).join( ', ' ) );
// => '[ 0, 3, 6 ]'
s1 = new Slice( null, 8, null );
s2 = normalizeSlice( s1, 10, false );
v = sliceLength( s2 );
console.log( '%s => %s => %d', s1.toString(), s2.toString(), v );
console.log( '[ %s ]', incrspace( s2.start, s2.stop || -1, s2.step ).join( ', ' ) );
// => '[ 0, 1, 2, 3, 4, 5, 6, 7 ]'
s1 = new Slice( -4, null, -2 );
s2 = normalizeSlice( s1, 10, false );
v = sliceLength( s2 );
console.log( '%s => %s => %d', s1.toString(), s2.toString(), v );
console.log( '[ %s ]', incrspace( s2.start, s2.stop || -1, s2.step ).join( ', ' ) );
// => '[ 6, 4, 2, 0 ]'
s1 = new Slice( null, 8, 3 );
s2 = normalizeSlice( s1, 10, false );
v = sliceLength( s2 );
console.log( '%s => %s => %d', s1.toString(), s2.toString(), v );
console.log( '[ %s ]', incrspace( s2.start, s2.stop || -1, s2.step ).join( ', ' ) );
// => '[ 0, 3, 6 ]'
s1 = new Slice( 8, 2, -2 );
s2 = normalizeSlice( s1, 10, false );
v = sliceLength( s2 );
console.log( '%s => %s => %d', s1.toString(), s2.toString(), v );
console.log( '[ %s ]', incrspace( s2.start, s2.stop || -1, s2.step ).join( ', ' ) );
// => '[ 8, 6, 4 ]'
s1 = new Slice( 3, 8, 2 );
s2 = normalizeSlice( s1, 10, false );
v = sliceLength( s2 );
console.log( '%s => %s => %d', s1.toString(), s2.toString(), v );
console.log( '[ %s ]', incrspace( s2.start, s2.stop || -1, s2.step ).join( ', ' ) );
// => '[ 3, 5, 7 ]'
```
* * *
## See Also
- [`@stdlib/slice-base/nonreduced-dimensions`][@stdlib/slice/base/nonreduced-dimensions]: return a list of non-reduced dimensions in an un-normalized multi-slice.
- [`@stdlib/slice-base/reduced-dimensions`][@stdlib/slice/base/reduced-dimensions]: return a list of reduced dimensions in an un-normalized multi-slice.
- [`@stdlib/slice-base/shape`][@stdlib/slice/base/shape]: compute the shape of a normalized multi-slice.
* * *
## 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 © 2016-2024. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/slice-base-length.svg
[npm-url]: https://npmjs.org/package/@stdlib/slice-base-length
[test-image]: https://github.com/stdlib-js/slice-base-length/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/slice-base-length/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/slice-base-length/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/slice-base-length?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/slice-base-length/tree/deno
[deno-readme]: https://github.com/stdlib-js/slice-base-length/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/slice-base-length/tree/umd
[umd-readme]: https://github.com/stdlib-js/slice-base-length/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/slice-base-length/tree/esm
[esm-readme]: https://github.com/stdlib-js/slice-base-length/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/slice-base-length/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/slice-base-length/main/LICENSE
[@stdlib/slice/base/normalize-slice]: https://github.com/stdlib-js/slice-base-normalize-slice
[@stdlib/slice/base/nonreduced-dimensions]: https://github.com/stdlib-js/slice-base-nonreduced-dimensions
[@stdlib/slice/base/reduced-dimensions]: https://github.com/stdlib-js/slice-base-reduced-dimensions
[@stdlib/slice/base/shape]: https://github.com/stdlib-js/slice-base-shape