가중치 랜덤 구하기

PHP

function weighted_random($weights)
{
  $r = rand(1, array_sum($weights));
  for($i=0; $i<count($weights); $i++) {
  $r -= $weights[$i];
  if($r < 1) return $i;
  }
  return false;
}

$values = array('a','b','c');
$weights = array(10,20,70);
for($i=0;$i<1000;$i++)
{
  $index = weighted_random($weights);
  echo "<br/>".$values[$index];
}