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at4d

Return an element from a four-dimensional nested array.

Installation

npm install @stdlib/array-base-at4d

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 at4d = require( '@stdlib/array-base-at4d' );

at4d( x, i0, i1, i2, i3 )

Returns an element from a four-dimensional nested array.

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

var out = at4d( x, 0, 0, 0, 1 );
// returns 2

out = at4d( x, 0, 0, 1, 0 );
// returns 3

The function accepts the following arguments:

• x: four-dimensional nested input array.
• i0: first dimension index.
• i1: second dimension index.
• i2: third dimension index.
• i3: fourth dimension index.

Notes

• Negative indices are resolved relative to the last element along the respective dimension, with the last element corresponding to -1.
• If provided out-of-bounds indices, the function always returns undefined.

Examples

var papply = require( '@stdlib/utils-papply' );
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' ).factory;
var filled4dBy = require( '@stdlib/array-base-filled4d-by' );
var quaternary4d = require( '@stdlib/array-base-quaternary4d' );
var zeros4d = require( '@stdlib/array-base-zeros4d' );
var at4d = require( '@stdlib/array-base-at4d' );

var shape = [ 2, 2, 4, 4 ];

// Define a nested input array:
var x = filled4dBy( shape, discreteUniform( -100, 100 ) );
console.log( x );

// Define arrays containing random index values:
var i0 = filled4dBy( shape, discreteUniform( -shape[0], shape[0]-1 ) );
console.log( i0 );

var i1 = filled4dBy( shape, discreteUniform( -shape[1], shape[1]-1 ) );
console.log( i1 );

var i2 = filled4dBy( shape, discreteUniform( -shape[2], shape[2]-1 ) );
console.log( i2 );

var i3 = filled4dBy( shape, discreteUniform( -shape[3], shape[3]-1 ) );
console.log( i3 );

// Define an output array:
var out = zeros4d( shape );
console.log( out );

// Fill the output array with randomly selected values from the input array:
quaternary4d( [ i0, i1, i2, i3, out ], shape, papply( at4d, x ) );
console.log( out );

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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.