is a recursive reducer to all permutations with repetitions of multi dimensional array indices
npm install indices-permutations> is a recursive reducer to all permutations with repetitions of multi dimensional array indices
Installation |
Usage |
Examples |
License
With npm do
``bash`
npm install indices-permutations
Use it as a callback for the Array.prototype.reduce()
on an array of positive integers. It returns the result array of all indices permutated.
Note that initialValue argument must be provided, for instance it can be an empty array [].
Both CommonJS and ES6 import syntax are supported.
`js`
import indicesPermutations from 'indicesPermutations'
`js`
const indicesPermutations = require('indices-permutations')
All code in the examples below is intended to be contained into a single file.
Reduce [n] to [[0], [1], ..., [n-1]]
`javaScript`
[5].reduce(indicesPermutations, []) // [[0], [1], [2], [3], [4]]
Reduce [m, n] to [[0, 0], [0, 1], ... ,[m-1, n-1]]
`javaScript`
[3, 3].reduce(indicesPermutations, []) // [[0, 0], [0, 1], [0, 2],
// [1, 0], [1, 1], [1, 2],
// [2, 0], [2, 1], [2, 2]]
Reduce [a1, a2, a3] to [[0, 0, 0], ... ,[a1 - 1, a2 - 1, a3 - 1]]
`javaScript``
[2, 2, 3].reduce(indicesPermutations, []) // [[0, 0, 0], [0, 0, 1], [0, 0, 2],
// [0, 1, 0], [0, 1, 1], [0, 1, 2],
// [1, 0, 0], [1, 0, 1], [1, 0, 2],
// [1, 1, 0], [1, 1, 1], [1, 1, 2]]