slastIndexOf

Return the last index of a search element in a one-dimensional single-precision floating-point ndarray.

Installation

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

Usage

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

slastIndexOf( arrays )

Returns the last index of a specified search element in a one-dimensional single-precision floating-point ndarray.

var Float32Array = require( '@stdlib/array-float32' );
var scalar2ndarray = require( '@stdlib/ndarray-from-scalar' );
var ndarray = require( '@stdlib/ndarray-base-ctor' );

var xbuf = new Float32Array( [ 1.0, 2.0, 4.0, 2.0 ] );
var x = new ndarray( 'float32', xbuf, [ 4 ], [ 1 ], 0, 'row-major' );

var searchElement = scalar2ndarray( 2.0, {
    'dtype': 'float32'
});

var fromIndex = scalar2ndarray( 3, {
    'dtype': 'generic'
});

var idx = slastIndexOf( [ 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 Float32Array = require( '@stdlib/array-float32' );
var scalar2ndarray = require( '@stdlib/ndarray-from-scalar' );
var ndarray = require( '@stdlib/ndarray-base-ctor' );

var xbuf = new Float32Array( [ 1.0, 2.0, 4.0, 2.0 ] );
var x = new ndarray( 'float32', xbuf, [ 4 ], [ 1 ], 0, 'row-major' );

var searchElement = scalar2ndarray( 10.0, {
    'dtype': 'float32'
});

var fromIndex = scalar2ndarray( 3, {
    'dtype': 'generic'
});

var idx = slastIndexOf( [ 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 slastIndexOf = require( '@stdlib/blas-ext-base-ndarray-slast-index-of' );

var xbuf = discreteUniform( 10, -100, 100, {
    'dtype': 'float32'
});
var x = new ndarray( 'float32', xbuf, [ xbuf.length ], [ 1 ], 0, 'row-major' );
console.log( ndarray2array( x ) );

var searchElement = scalar2ndarray( 80.0, {
    'dtype': 'float32'
});
console.log( 'Search Element:', ndarraylike2scalar( searchElement ) );

var fromIndex = scalar2ndarray( -1, {
    'dtype': 'generic'
});
console.log( 'From Index:', ndarraylike2scalar( fromIndex ) );

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

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.