wrand(); // A PHP weighted randomization function

Dan from todaywasawesome just asked me to help him with a weighted randomization function in PHP. I thought my solution was cool, if a bit simplistic. Like everything else I want to keep around, I’m posting it in my blag. Enjoy!


 * This function expects an array with weights
 * as its array indices. You should not use a
 * simple array — e.g. array('a', 'b', 'c'). Since
 * the first item in an array like this has index 0,
 * it will never be selected.
 * It will return a randomly selected value.
function wrand($data) {
    $totalw = array_sum(array_keys($data));
    $rand   = rand(1, $totalw);
    $curw   = 0;
    foreach ($data as $i => $val) {
        $curw += $i;
        if ($curw >= $rand) return $val;
    return end($data);