PHP概率算法（适用于抽奖）

function get_rand(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'=>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),
);