About stdlib...

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.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

takeIndexed

Take elements from an indexed array.

Installation

npm install @stdlib/array-base-take-indexed

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md 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

var takeIndexed = require( '@stdlib/array-base-take-indexed' );

takeIndexed( x, indices )

Takes elements from an indexed array.

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

var y = takeIndexed( x, [ 1, 3 ] );
// returns [ 2, 4 ]

If indices is an empty array, the function returns an empty array.

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

var y = takeIndexed( x, [] );
// returns []

Notes

• The function does not perform bounds checking. If an index is less than zero or greater than the maximum index of x, the value of the corresponding element in the output array is undefined.
• An indexed array-like object is a data structure in which one retrieves elements via integer indices using bracket [] notation (e.g., Float64Array, Int32Array, Array, etc). This is in contrast to an accessor array-like object in which one retrieves elements using get and set methods (e.g., Complex64Array and Complex128Array).

Examples

var filledBy = require( '@stdlib/array-base-filled-by' );
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var linspace = require( '@stdlib/array-base-linspace' );
var takeIndexed = require( '@stdlib/array-base-take-indexed' );

// Generate a linearly spaced array:
var x = linspace( 0, 100, 11 );

// Generate an array of random indices:
var N = discreteUniform( 5, 15 );
var indices = filledBy( N, discreteUniform.factory( 0, x.length-1 ) );

// Take a random sample of elements from `x`:
var y = takeIndexed( x, indices );

console.log( x );
console.log( indices );
console.log( y );

---

Notice

This package is part of 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, see the main project repository.

Community

---

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.