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glastIndexOf

Return the last index of a search element in a one-dimensional ndarray.

Installation

npm install @stdlib/blas-ext-base-ndarray-glast-index-of

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var glastIndexOf = require( '@stdlib/blas-ext-base-ndarray-glast-index-of' );

glastIndexOf( arrays )

Returns the last index of a specified search element in a one-dimensional ndarray.

var scalar2ndarray = require( '@stdlib/ndarray-from-scalar' );
var ndarray = require( '@stdlib/ndarray-base-ctor' );

var xbuf = [ 1.0, 2.0, 4.0, 2.0 ];
var x = new ndarray( 'generic', xbuf, [ 4 ], [ 1 ], 0, 'row-major' );

var searchElement = scalar2ndarray( 2.0, {
    'dtype': 'generic'
});

var fromIndex = scalar2ndarray( 0, {
    'dtype': 'generic'
});

var idx = glastIndexOf( [ x, searchElement, fromIndex ] );
// returns 3

The function has the following parameters:

• arrays: array-like object containing the following ndarrays:

  • a one-dimensional input ndarray.
  • a zero-dimensional ndarray containing the search element.
  • a zero-dimensional ndarray containing the index from which to begin searching.

If the function is unable to find a search element, the function returns -1.

var scalar2ndarray = require( '@stdlib/ndarray-from-scalar' );
var ndarray = require( '@stdlib/ndarray-base-ctor' );

var xbuf = [ 1.0, 2.0, 4.0, 2.0 ];
var x = new ndarray( 'generic', xbuf, [ 4 ], [ 1 ], 0, 'row-major' );

var searchElement = scalar2ndarray( 10.0, {
    'dtype': 'generic'
});

var fromIndex = scalar2ndarray( 0, {
    'dtype': 'generic'
});

var idx = glastIndexOf( [ x, searchElement, fromIndex ] );
// returns -1

Notes

• If a specified starting search index is negative, the function resolves the starting search index by counting backward from the last element (where -1 refers to the last element).

Examples

var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var ndarray = require( '@stdlib/ndarray-base-ctor' );
var scalar2ndarray = require( '@stdlib/ndarray-from-scalar' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var ndarraylike2scalar = require( '@stdlib/ndarray-base-ndarraylike2scalar' );
var glastIndexOf = require( '@stdlib/blas-ext-base-ndarray-glast-index-of' );

var xbuf = discreteUniform( 10, -100, 100, {
    'dtype': 'generic'
});
var x = new ndarray( 'generic', xbuf, [ xbuf.length ], [ 1 ], 0, 'row-major' );
console.log( ndarray2array( x ) );

var searchElement = scalar2ndarray( 80.0, {
    'dtype': 'generic'
});
console.log( 'Search Element:', ndarraylike2scalar( searchElement ) );

var fromIndex = scalar2ndarray( 0, {
    'dtype': 'generic'
});
console.log( 'From Index:', ndarraylike2scalar( fromIndex ) );

var idx = glastIndexOf( [ x, searchElement, fromIndex ] );
console.log( idx );

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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

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License

See LICENSE.

Copyright

Copyright © 2016-2025. The Stdlib Authors.