Array (
‘id’ => ‘weight’
}

$cweights = count($weights);
for ($i=0; $i<$cweights; $i++) {

Thanks for the code I think I’ll use it.

function weighted_random_simple($values, $weights){
$total = array_sum($weights);
$n = 0;
$num = mt_rand(1, $total);
foreach ($values as $i => $value) {
$n += $weights[$i];
if ($n >= $num){
return $values[$i];
}
}
}

in mt_rand() the $min value must be 1, not zero, since $min and $max are both included. Begining with zero you give the first element the probability of zero plus the probability of the weight.

for ($i=0, $cweights = count($weights); $i < count($weights); $i++) {

than

$cweights = count($weights);
for ($i=0; $i<count($weights); $i++) {

btw, the article seems to be look. I haven't read it yet.

$cweights = count($weights);
for ($i=0; $i<count($weights); $i++) {

instead of:

for ($i=0; $i<count($weights); $i++) {

that way the 'count' function isn't called each iteration of the loop.

You could also do small things like remove function paramters from the main function and just force a call to list($lookup, $total_weight) = calc_lookups($values, $weights);, or use incrementation like ++$i; instead of $i++, which executes faster.