reducedDimensions

Return a list of reduced dimensions in an un-normalized MultiSlice object.

In a multi-axis indexing expression (e.g., '1,:,2,:,0:10:1'), a non-reduced dimension corresponds to a dimension which is retained in the slice result. Only integer indexing expressions (e.g., only the first and third dimensions in '1,:,2,:,0:10:1') result in dimension reduction; slices always retain respective dimensions, even if a slice is empty or only selects a single element.

Installation

npm install @stdlib/slice-base-reduced-dimensions

Usage

var reducedDimensions = require( '@stdlib/slice-base-reduced-dimensions' );

reducedDimensions( slice )

Return a list of reduced dimensions in an un-normalized MultiSlice object.

var MultiSlice = require( '@stdlib/slice-multi' );
var Slice = require( '@stdlib/slice-ctor' );

var s = new MultiSlice( 1, null, 2, void 0, new Slice( 0, 10, 1 ) );
// returns <MultiSlice>

var indices = reducedDimensions( s );
// returns [ 0, 2 ]

Examples

var S = require( '@stdlib/slice-ctor' );
var MultiSlice = require( '@stdlib/slice-multi' );
var reducedDimensions = require( '@stdlib/slice-base-reduced-dimensions' );

var s = new MultiSlice( null, S(), -1 );
var out = reducedDimensions( s );
console.log( '%s => [%s]', s.toString(), out.join( ',' ) );

s = new MultiSlice( null );
out = reducedDimensions( s );
console.log( '%s => [%s]', s.toString(), out.join( ',' ) );

s = new MultiSlice( S( -1, null, -1 ), 3 );
out = reducedDimensions( s );
console.log( '%s => [%s]', s.toString(), out.join( ',' ) );

s = new MultiSlice( 2, S( -10, -2, 2 ), 3, null );
out = reducedDimensions( s );
console.log( '%s => [%s]', s.toString(), out.join( ',' ) );

s = new MultiSlice( S( 1, 20, 2 ), S( null, null, -1 ) );
out = reducedDimensions( s );
console.log( '%s => [%s]', s.toString(), out.join( ',' ) );

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 © 2016-2024. The Stdlib Authors.