README.md

About stdlib...

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take

Take elements from an array.

Installation

npm install @stdlib/array-take

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 take = require( '@stdlib/array-take' );

take( x, indices[, options] )

Takes elements from an array.

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

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

The function supports the following parameters:

• x: input array.
• indices: list of indices.
• options: function options.

The function supports the following options:

• mode: index mode. Default: 'normalize'.

By default, the function normalizes negative integer indices to positive integer index equivalents.

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

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

To specify an alternative index mode, provide a mode option.

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

var y = take( x, [ -10, 10 ], {
    'mode': 'clamp'
});
// returns [ 1, 4 ]

Notes

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

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

• If provided an input array having a recognized data type, the function returns an array having the same data type as the input array. Otherwise, the function always returns a "generic" array.

Examples

var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var linspace = require( '@stdlib/array-linspace' );
var take = require( '@stdlib/array-take' );

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

// Generate an array of random indices:
var indices = discreteUniform( 10, 0, x.length-1 );
console.log( indices );

// Take a random sample of elements from `x`:
var y = take( x, indices );
console.log( y );

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See Also

• @stdlib/array-slice: return a shallow copy of a portion of an array.

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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

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.