Question

Anyone have a function to create 4D arrays (or any number of dimensions for that matter)?

I’d like to call the function, then after that I can do something like arr[3][2][23][12] = "awesome";

Answer 1

function make(dim, lvl, arr) {
  if (lvl === 1) return [];
  if (!lvl) lvl = dim;
  if (!arr) arr = [];
  for (var i = 0, l = dim; i < l; i += 1) {
    arr[i] = make(dim, lvl - 1, arr[i]);
  }
  return arr;
}

var myMultiArray = make(4);

Update: you can specify how deep a level should be in the first parameter, and how many levels in the second. e.g.:

var myMultiArray = make(64, 4);

This will allow you to set and get in this format:

myMultiArray[X][X][X][X] = ....

But X must always be less than 64. You cannot set myMultiArray[X][70][X][X] for example, because myMultiArray[X][70] has not yet been defined

Note- running make(64, 4) is awfully slow – you are creating 64 ^ 4 empty array elements (i.e. 16,777,216).

Update 2: you can get away with the last value as any number or string. Ie. myMultiArray[X][X][X][Y] where X < 64 and Y can be anything.

The algorithm has been optimised as well, give it another go.