fillBy

Fill an input ndarray according to a callback function.

Installation

npm install @stdlib/ndarray-fill-by

Usage

var fillBy = require( '@stdlib/ndarray-fill-by' );

fillBy( x, fcn[, thisArg] )

Fills an input ndarray according to a callback function.

var zeros = require( '@stdlib/ndarray-zeros' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );

function fcn( value ) {
    return value + 10.0;
}

var x = zeros( [ 3, 1, 2 ], {
    'dtype': 'float64'
});

var y = fillBy( x, fcn );
// returns <ndarray>

var bool = ( y === x );
// returns true

var arr = ndarray2array( y );
// returns [ [ [ 10.0, 10.0 ] ], [ [ 10.0, 10.0 ] ], [ [ 10.0, 10.0 ] ] ]

The function accepts the following arguments:

• x: array-like object containing an input ndarray.
• fcn: callback function.
• thisArg: callback function execution context (optional).

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

var zeros = require( '@stdlib/ndarray-zeros' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );

function fcn( value ) {
    return value + this.factor;
}

var x = zeros( [ 3, 1, 2 ], {
    'dtype': 'float64'
});

var ctx = {
    'factor': 10.0
};
var y = fillBy( x, fcn, ctx );
// returns <ndarray>

var arr = ndarray2array( y );
// returns [ [ [ 10.0, 10.0 ] ], [ [ 10.0, 10.0 ] ], [ [ 10.0, 10.0 ] ] ]

The callback function is provided the following arguments:

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

Notes

• An input ndarray must be writable. If provided a read-only ndarray, the function throws an error.
• The function mutates the input ndarray.
• The function assumes that each element in the underlying input ndarray data buffer has one, and only one, corresponding element in input ndarray view (i.e., a provided ndarray is not a broadcasted ndarray view).

Examples

var discreteUniform = require( '@stdlib/random-base-discrete-uniform' ).factory;
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var zeros = require( '@stdlib/ndarray-zeros' );
var fillBy = require( '@stdlib/ndarray-fill-by' );

// Create a zero-filled ndarray:
var x = zeros( [ 5, 2 ], {
    'dtype': 'generic'
});
console.log( ndarray2array( x ) );

// Fill the ndarray with random values:
fillBy( x, discreteUniform( -100, 100 ) );
console.log( ndarray2array( x ) );

See Also

• @stdlib/ndarray-fill: fill an input ndarray with a specified value.
• @stdlib/ndarray-map: apply a callback to elements in an input ndarray and assign results to elements in a new output ndarray.
• @stdlib/ndarray-zeros: create a zero-filled ndarray having a specified shape and data type.

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 © 2016-2026. The Stdlib Authors.