PHP 抽奖demo

<?php/** * 根据概率获取奖项ID * @param proArr array 以奖品id为key，概率为value的数组 * @return $result 中奖奖品id */function get_rand($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 $result; } //1. 从数据库读奖品概率$prize_arr = array(   '0' => array('id'=>1,'prize'=>'平板电脑','v'=>1),   '1' => array('id'=>2,'prize'=>'数码相机','v'=>5),   '2' => array('id'=>3,'prize'=>'音箱设备','v'=>10),   '3' => array('id'=>4,'prize'=>'4G优盘','v'=>12),   '4' => array('id'=>5,'prize'=>'10Q币','v'=>22),   '5' => array('id'=>6,'prize'=>'下次没准就能中哦','v'=>50), ); //2. 提取奖品ID对应的概率数组 foreach ($prize_arr as $key => $val) {    $arr[$val['id']] = $val['v'];  } //["1"=>1,"2"=>5,"3"=>10,"4"=>12,"5"=>22,"6"=>50]//3. 获取是否中奖 $rid = get_rand($arr); //根据概率获取奖项id  $res['yes'] = $prize_arr[$rid-1]['prize']; //中奖项  unset($prize_arr[$rid-1]); //将中奖项从数组中剔除，剩下未中奖项  shuffle($prize_arr); //打乱数组顺序  for($i=0;$i<count($prize_arr);$i++){    $pr[] = $prize_arr[$id]['prize'];  }  $res['no'] = $pr;  echo json_encode($res);?>