php简单中奖算法(实例)

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,'prize'=>'平板电脑','v'=>0.1),
'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),
);


foreach ($prize_arr as $key => $val) {
$arr[$val['id']] = $val['v'];
}
$rid = get_rand($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[] = $prize_arr[$i]['prize'];
}
$res['no'] = $pr;
echo json_encode($res,JSON_UNESCAPED_UNICODE);