lodash.permutations
v1.0.0
Published
Calculates all possible permutations of a certain size.
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lodash.permutations
_.permutations(collection, n)
Calculates all possible permutations of a certain size.
| argument | description |
| ---: | :--- |
| collection
| A collection of distinct values to calculate the permutations from. |
| n
| The number of values to combine. |
Returns a new array.
setup
npm
npm i lodash.permutations
ES module
import 'lodash.permutations';
import _ from 'lodash';
Node
require('lodash.permutations');
let _ = require('lodash');
browser
<script src="https://unpkg.com/lodash"></script>
<script src="https://unpkg.com/lodash.permutations"></script>
usage
let permutations = _.permutations([true, {a: 1}, null], 2);
// => [[true, {a: 1}], [true, null], [{a: 1}, true], [{a: 1}, null], [null, true], [null, {a: 1}]]
Calculate all possible permutations of all possible sizes.
let permutations = _.flatMap([2, 4, 6], (v, i, a) => _.permutations(a, i + 1));
// => [[2], [4], [6], [2, 4], [2, 6], [4, 2], [4, 6], [6, 2], [6, 4], [2, 4, 6], [2, 6, 4], [4, 2, 6], [4, 6, 2], [6, 2, 4], [6, 4, 2]]
Also accepts array-like values.
let permutations = _('abc').permutations(3).map(v => _.join(v, '')).value();
// => ['abc', 'acb', 'bac', 'bca', 'cab', 'cba']