subsequences

List all possible subsequences.

Similar: randomSubsequence, subsequences, hasSubsequence, searchSubsequence.

function subsequences(x, n)
// x: an array
// n: number of values [-1 ⇒ any]

const array = require('extra-array');

[...array.subsequences([1, 2])];
// → [ [], [ 1 ], [ 2 ], [ 1, 2 ] ]

[...array.subsequences([1, 2, 3])];
// → [
//   [],       [ 1 ],
//   [ 2 ],    [ 1, 2 ],
//   [ 3 ],    [ 1, 3 ],
//   [ 2, 3 ], [ 1, 2, 3 ]
// ]

References

• Data.List.subsequences: Haskell