at3d

Return an element from a three-dimensional nested array.

Usage

var at3d = require( '@stdlib/array/base/at3d' );

at3d( x, i0, i1, i2 )

Returns an element from a three-dimensional nested array.

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

var out = at3d( x, 0, 0, 1 );
// returns 2

out = at3d( x, 0, 1, 0 );
// returns 3

The function accepts the following arguments:

x: three-dimensional nested input array.
i0: first dimension index.
i1: second dimension index.
i2: third 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 filled3dBy = require( '@stdlib/array/base/filled3d-by' );
var ternary3d = require( '@stdlib/array/base/ternary3d' );
var zeros3d = require( '@stdlib/array/base/zeros3d' );
var at3d = require( '@stdlib/array/base/at3d' );

var shape = [ 3, 3, 3 ];

// Define a nested input array:
var x = filled3dBy( shape, discreteUniform( -100, 100 ) );
console.log( x );

// Define arrays containing random index values:
var i0 = filled3dBy( shape, discreteUniform( -shape[0], shape[0]-1 ) );
console.log( i0 );

var i1 = filled3dBy( shape, discreteUniform( -shape[1], shape[1]-1 ) );
console.log( i1 );

var i2 = filled3dBy( shape, discreteUniform( -shape[2], shape[2]-1 ) );
console.log( i2 );

// Define an output array:
var out = zeros3d( shape );
console.log( out );

// Fill the output array with randomly selected values from the input array:
ternary3d( [ i0, i1, i2, out ], shape, papply( at3d, x ) );
console.log( out );