Question

Assuming we have:

array1 = ['A', 'B', 'C', 'D', 'E']; array2 = ['C', 'E'];

Is there a proven and fast solution to compare two arrays against each other, returning one array without the values appearing in both arrays (C and E here).
So:

array3 = ['A', 'B', 'D']

should be the output of the solution. (jquery may be involved)

thx.

Answer 1

This is a set difference. A simple implementation is:

jQuery.grep(array1, function(el)
                    {
                        return jQuery.inArray(el, array2) == -1;
                    });

This is O(m * n), where those are the sizes of the arrays. You can do it in O(m + n), but you need to use some kind of hash set. You can use a JavaScript object as a simple hash set for strings. For relatively small arrays, the above should be fine.