抽奖概率计算

function get_rand($proArr) {
$result = '';
//概率数组的总概率精度
$proSum = array_sum($proArr);
//概率数组循环
foreach ($proArr as $key => $proCur) {
$randNum = mt_rand(1, $proSum);
if ($randNum <= $proCur) {
$result = $key;
break;
} else {
$proSum -= $proCur;
}
}
unset ($proArr);
return $result;
}

$rid = $this->get_rand($arr); //根据概率获取奖项id

foreach($plist as $key => $val){ if($val['prize_id'] == $rid){ $res['yes'] = $val['prize_name']; //中奖项 } }