/** * @license Apache-2.0 * * Copyright (c) 2022 The Stdlib Authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ 'use strict'; // MODULES // var resolveGetter = require( './../../../base/resolve-getter' ); var ind = require( '@stdlib/ndarray/base/ind' ).factory; // MAIN // /** * Takes elements from an array. * * @param {Collection} x - input array * @param {IntegerArray} indices - list of indices * @param {string} mode - index mode * @returns {Array} output array * * @example * var x = [ 1, 2, 3, 4 ]; * var indices = [ 3, 1, 2, 0 ]; * * var y = take( x, indices, 'throw' ); * // returns [ 4, 2, 3, 1 ] */ function take( x, indices, mode ) { var getIndex; var xget; var iget; var out; var max; var i; var j; // Resolve an accessor for retrieving array elements: xget = resolveGetter( x ); iget = resolveGetter( indices ); // Resolve a function for returning an index according to the specified index mode: getIndex = ind( mode ); // Resolve the maximum index: max = x.length - 1; // Extract each desired element from the provided array... out = []; for ( i = 0; i < indices.length; i++ ) { j = getIndex( iget( indices, i ), max ); out.push( xget( x, j ) ); // use `Array#push` to ensure "fast" elements } return out; } // EXPORTS // module.exports = take;