Javascript compare items in one array

Question

Pardon my complete lack of javascript knowledge in advance, but I can\'t seem to find a good example of how to compare two arrays and create another array based the results.

Answer 1

I like the indexOf method for this. Example fiddle: http://jsfiddle.net/8MV3J/

var good = ["someuser1", "someuser2", "someuser3"];
var bad = [];
var ugly = ["someuser4", "someuser1", "someuser5", "someuser2", "someuser6", "someuser3", "someuser7"];
var i = 0;
var li;

for (i = 0; i < ugly.length; i += 1) {
    if (good.indexOf(ugly[i]) === -1) {
        bad.push(ugly[i]);
    }
}

for (i = 0; i < bad.length; i += 1) {
    li = $('
').text(bad[i]);
    $('ul#bad').append(li);
}​