How to rearrange an array by indices array?

Question

Given an array arr and an array of indices ind, I\'d like to rearrange arr in-place to satisfy the given indices. For exa

Answer 1

I'm not sure on the time, but the map function does appear to do what was requested. It's an option, but since I don't know the inner workings of .map then I can't say for sure this is what you're looking for.

var arr = ["A", "B", "C", "D", "E", "F"];
var ind = [4, 0, 5, 2, 1, 3];

arr = ind.map(function(value)
{ return arr[value]; });

Another solution that doesn't use the map function could look something like this:

var arr = ["A", "B", "C", "D", "E", "F"];
var ind = [4, 0, 5, 2, 1, 3];

var temp = [];

for (var i = 0, ind_length = ind.length; i < ind_length; i++) 
{ 
    var set_index = ind[i];
    temp.push(arr[set_index]); 
    delete arr[set_index]; 
}

arr = temp;

This makes good use of space by using the delete option which also keeps the indexes from shifting. Since it's only doing one loop I imagine the execution is rather fast. Since the commands are very basic and simple this should be a viable solution. It's not quite what was asked which was a swap with no extra space used, but it comes pretty close. I'm new to answering questions like this one so please... constructive criticism.