select random value NOT in array

Question

How would I select a random value (0 to 30) that is not in this array?

var list = new Array(1,3,4,7,8,9);

Answer 1

You need a while loop that tests if rand is in your restricted array and, if so, re-generate a new random number:

var rand;
do {
    rand = Math.floor(Math.random() * 31); // re-randomize, 0 to 30 inclusive
} while ($.inArray(rand, restricted) > -1);
return rand;

http://jsfiddle.net/mblase75/dAN8R/

Don't want jQuery? You can replace $.inArray(rand, restricted) with restricted.indexOf(rand) if you use this polyfill for old browsers.