permute.js (1186B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2021 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 'use strict'; 20 21 // MAIN // 22 23 /** 24 * Returns a permutation of an input array according to a provided index array. 25 * 26 * @private 27 * @param {Collection} x - input array 28 * @param {NonNegativeIntegerArray} idx - permutation indices 29 * @returns {Array} output array 30 * 31 * @example 32 * var x = [ 1, 2, 3, 4 ]; 33 * var idx = [ 3, 1, 2, 0 ]; 34 * 35 * var y = permute( x, idx ); 36 * // returns [ 4, 2, 3, 1 ] 37 */ 38 function permute( x, idx ) { 39 var out; 40 var i; 41 42 out = []; 43 for ( i = 0; i < x.length; i++ ) { 44 out.push( x[ idx[ i ] ] ); 45 } 46 return out; 47 } 48 49 50 // EXPORTS // 51 52 module.exports = permute;