fillSlice

Fill an input ndarray view with a specified value.

Installation

npm install @stdlib/ndarray-fill-slice

Usage

var fillSlice = require( '@stdlib/ndarray-fill-slice' );

fillSlice( x, value, ...s[, options] )

Fills an input ndarray view with a specified value.

var zeros = require( '@stdlib/ndarray-zeros' );
var MultiSlice = require( '@stdlib/slice-multi' );
var Slice = require( '@stdlib/slice-ctor' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );

var x = zeros( [ 3, 4 ], {
    'dtype': 'float64'
});

// Define the fill region:
var s0 = new Slice( 1, 3 );
var s1 = new Slice( 2, 4 );
var s = new MultiSlice( s0, s1 );

// Fill the region with a scalar value:
var y = fillSlice( x, 5.0, s );
// returns <ndarray>

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

var arr = ndarray2array( x );
// returns [ [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 5.0, 5.0 ], [ 0.0, 0.0, 5.0, 5.0 ] ]

The function accepts the following arguments:

• x: input ndarray.
• value: fill value.
• s: a MultiSlice instance, an array of slice arguments, or slice arguments as separate arguments.
• options: function options.

The function supports three (mutually exclusive) means for providing slice arguments:

1. providing a single MultiSlice instance.
2. providing a single array of slice arguments.
3. providing slice arguments as separate arguments.

The following example demonstrates each invocation style achieving equivalent results.

var zeros = require( '@stdlib/ndarray-zeros' );
var MultiSlice = require( '@stdlib/slice-multi' );
var Slice = require( '@stdlib/slice-ctor' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );

var opts = {
    'dtype': 'float64'
};

// 1. Using a MultiSlice:
var x = zeros( [ 3, 4 ], opts );

var s0 = new Slice( 1, 3 );
var s1 = new Slice( 2, 4 );
var s = new MultiSlice( s0, s1 );

var out = fillSlice( x, 5.0, s );
// returns <ndarray>

var arr = ndarray2array( out );
// returns [ [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 5.0, 5.0 ], [ 0.0, 0.0, 5.0, 5.0 ] ]

// 2. Using an array of slice arguments:
x = zeros( [ 3, 4 ], opts );

out = fillSlice( x, 6.0, [ s0, s1 ] );
// returns <ndarray>

arr = ndarray2array( out );
// returns [ [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 6.0, 6.0 ], [ 0.0, 0.0, 6.0, 6.0 ] ]

// 3. Providing separate arguments:
x = zeros( [ 3, 4 ], opts );

out = fillSlice( x, 7.0, s0, s1 );
// returns <ndarray>

arr = ndarray2array( out );
// returns [ [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 7.0, 7.0 ], [ 0.0, 0.0, 7.0, 7.0 ] ]

The function supports the following options:

• strict: boolean indicating whether to enforce strict bounds checking.

By default, the function throws an error when provided a slice which exceeds array bounds. To ignore slice indices exceeding array bounds, set the strict option to false.

var zeros = require( '@stdlib/ndarray-zeros' );
var MultiSlice = require( '@stdlib/slice-multi' );
var Slice = require( '@stdlib/slice-ctor' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );

var x = zeros( [ 3, 4 ], {
    'dtype': 'float64'
});

// Define the fill region:
var s0 = new Slice( 1, null, 1 );
var s1 = new Slice( 10, 20, 1 );
var s = new MultiSlice( s0, s1 );

// Fill the region with a scalar value:
var y = fillSlice( x, 5.0, s, {
    'strict': false
});
// returns <ndarray>

var arr = ndarray2array( x );
// returns [ [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 0.0, 0.0 ] ]

Notes

• An input ndarray must be writable. If provided a read-only ndarray, the function throws an error.
• A slice argument must be either a Slice, an integer, null, or undefined.
• If a fill value is a number and x has a complex data type, the function fills an input ndarray with a complex number whose real component equals the provided fill value and whose imaginary component is zero.
• A fill value must be able to safely cast to the input ndarray data type. Fill values having floating-point data types (both real and complex) are allowed to downcast to a lower precision data type of the same kind (e.g., a scalar double-precision floating-point number can be used to fill a 'float32' input ndarray).
• The function mutates the input ndarray.

Examples

var zeros = require( '@stdlib/ndarray-zeros' );
var MultiSlice = require( '@stdlib/slice-multi' );
var Slice = require( '@stdlib/slice-ctor' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var fillSlice = require( '@stdlib/ndarray-fill-slice' );

// Create a zero-filled ndarray:
var x = zeros( [ 2, 3, 4 ], {
    'dtype': 'generic'
});
console.log( ndarray2array( x ) );

// Specify the fill region:
var s0 = new Slice( 1, 2 );
var s1 = new Slice( null, null );
var s2 = new Slice( 2, 4 );
var s = new MultiSlice( s0, s1, s2 );

// Fill a slice with a scalar value:
fillSlice( x, 10.0, s );
console.log( ndarray2array( x ) );

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.