Question

In javascript, I have an array:

letterArray ['a', 'e', 'i', 'o', 'u']

corresponding to that array, I have another array:

valueArray [12, 22, 7, 7, 3]

I want to sort the valueArray into

[22, 12, 7, 7, 3]

but the letterArray also needs to be sorted the same way:

['e', 'a', 'i', 'o', 'u']

How would I be able to do this?

Answer 1

You can do this using zipping method. I would use _.zip.

// [["a", 12], ["e", 22], ...]
var arr = _.zip(letterArray, valueArray); // zip them up.
// sort
// [["u", 3], ["i", 7] OR ["o", 7], ...]
var sortedArr = _.sortBy(arr, function(val) {
    // sort by the value array.
    return val[1];
});
// pluck the letter array back out
// ["u", "i" OR "o", ...]
var newLetterArray = _.pluck(sortedArr, "0");
// pluck the value array back out
// [3, 7, 7, ...]
var newValueArray = _.pluck(sortedArr, "1");

I’m afraid your example is complicated by having duplicate numbers which means you can not garantuee order on sorting. This is browser specific whether “i” or “o” comes first.