Question

I have two arrays and want to remove from one all elements which exist in the other as well.

• Can this be done with native JS?
• Is there a jQuery function to do it?
• What are best practices to do so (the
  faster the better)

p.s.: just post code in other languages too, maybe I can port it to Javascript

Update, after accepting answer to help the JS dudes 😉

// Array Remove - By John Resig (MIT Licensed)
Array.prototype.remove = function(from, to) {
    var rest = this.slice((to || from) + 1 || this.length);
    this.length = from < 0 ? this.length + from : from;
    return this.push.apply(this, rest);
};
// Array Contains - By Helmuth Lammer (TU Vienna)
Array.prototype.contains = function(key){

    for(var i = 0; i<this.length; i++){
        if(this[i]  == key) return i;
    }

    return false;
}

(There is a native JS method named contains too, but it should work)

Answer 1

Given two sets a and b, to remove all elements present in a from b. Translation to array formatting and javascript left as an exercise to the reader. Optimizations exist for sorted arrays.

for(element e : b) {
    if(a.contains(e)) {
         b.remove(e);
    }
}