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forEach

Invoke a callback function once for each ndarray element.

Usage

import forEach from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-for-each@deno/mod.js';

forEach( x, fcn[, thisArg] )

Invokes a callback function once for each ndarray element.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@deno/mod.js';
import ndarray from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-ctor@deno/mod.js';
import naryFunction from 'https://cdn.jsdelivr.net/gh/stdlib-js/utils-nary-function@deno/mod.js';
import log from 'https://cdn.jsdelivr.net/gh/stdlib-js/console-log@deno/mod.js';

var buffer = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
var shape = [ 2, 3 ];
var strides = [ 6, 1 ];
var offset = 1;

var x = ndarray( 'float64', buffer, shape, strides, offset, 'row-major' );
// returns <ndarray>

forEach( x, naryFunction( log, 1 ) );

The function accepts the following arguments:

• x: input ndarray.
• fcn: callback to apply.
• thisArg: callback execution context (optional).

To set the callback function execution context, provide a thisArg.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@deno/mod.js';
import ndarray from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-ctor@deno/mod.js';

function accumulate( z ) {
    this.sum += z;
}

var buffer = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
var shape = [ 2, 3 ];
var strides = [ 6, 1 ];
var offset = 1;
var x = ndarray( 'float64', buffer, shape, strides, offset, 'row-major' );
// returns <ndarray>

var ctx = {
    'sum': 0
};

forEach( x, accumulate, ctx );
var sum = ctx.sum;
// returns 36

The callback function is provided the following arguments:

• value: current array element.
• indices: current array element indices.
• arr: the input ndarray.

Notes

• For very high-dimensional ndarrays which are non-contiguous, one should consider copying the underlying data to contiguous memory before applying a callback function in order to achieve better performance.

Examples

import discreteUniform from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-array-discrete-uniform@deno/mod.js';
import ndarray from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-ctor@deno/mod.js';
import ndarray2array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-to-array@deno/mod.js';
import naryFunction from 'https://cdn.jsdelivr.net/gh/stdlib-js/utils-nary-function@deno/mod.js';
import log from 'https://cdn.jsdelivr.net/gh/stdlib-js/console-log@deno/mod.js';
import forEach from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-for-each@deno/mod.js';

var buffer = discreteUniform( 10, -100, 100, {
    'dtype': 'generic'
});
var shape = [ 5, 2 ];
var strides = [ 2, 1 ];
var offset = 0;
var x = ndarray( 'generic', buffer, shape, strides, offset, 'row-major' );

log( ndarray2array( x ) );
forEach( x, naryFunction( log, 2 ) );

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See Also

• @stdlib/ndarray-map: apply a callback to elements in an input ndarray and assign results to elements in a new output ndarray.

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Notice

This package is part of stdlib, a standard library 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 © 2016-2025. The Stdlib Authors.