PHP概率抽奖实现

<?php

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;
}

$prize_arr = array(
    '0' => array('id'=>1,'name'=>"ipad",'probability'=>1,'img'=>'','intro'=>''),
    '1' => array('id'=>2,'name'=>"carema",'probability'=>5,'img'=>'','intro'=>''),
    '2' => array('id'=>3,'name'=>"ipod",'probability'=>30,'img'=>'','intro'=>''),
    '3' => array('id'=>4,'name'=>"4GTF",'probability'=>2,'img'=>'','intro'=>''),
    '4' => array('id'=>5,'name'=>"10QB",'probability'=>12,'img'=>'','intro'=>''),
    '5' => array('id'=>6,'name'=>"No prize!",'probability'=>50,'img'=>'','intro'=>''),
); 
foreach ($prize_arr as $key => $val) {
    $arr[$val['id']] = $val['probability'];
}
 
$rid = get_rand($arr); //根据概率获取奖项id
 
$res['yes'] = $prize_arr[$rid-1]; //中奖项
//将中奖项从数组中剔除，剩下未中奖项，如果是数据库验证，这里可以省掉
unset($prize_arr[$rid-1]);
shuffle($prize_arr); //打乱数组顺序
for($i=0;$i<count($prize_arr);$i++){
    $pr[] = $prize_arr[$i];
}
$res['no'] = $pr;
var_dump($res);