php 抽奖概率 随机数

<?php

$prize_arr = array( 
    ‘0‘ => array(‘id‘ => 1, ‘title‘ => ‘iphone5s‘, ‘v‘ => 5), 
    ‘1‘ => array(‘id‘ => 2, ‘title‘ => ‘联系笔记本‘, ‘v‘ => 10), 
    ‘2‘ => array(‘id‘ => 3, ‘title‘ => ‘音箱设备‘, ‘v‘ => 20), 
    ‘3‘ => array(‘id‘ => 4, ‘title‘ => ‘30GU盘‘, ‘v‘ => 30), 
    ‘4‘ => array(‘id‘ => 5, ‘title‘ => ‘话费50元‘, ‘v‘ => 10), 
    ‘5‘ => array(‘id‘ => 6, ‘title‘ => ‘iphone6s‘, ‘v‘ => 15), 
    ‘6‘ => array(‘id‘ => 7, ‘title‘ => ‘谢谢，继续加油哦！~‘, ‘v‘ => 10), 
); 
 
foreach ($prize_arr as $key => $val) { 
    $arr[$val[‘id‘]] = $val[‘v‘]; 
} 
 
$prize_id = getRand($arr); //根据概率获取奖品id 
$data[‘msg‘] = ($prize_id == 7) ? 0 : 1; //如果为0则没中  
$data[‘prize_title‘] = $prize_arr[$prize_id - 1][‘title‘]; //中奖奖品 
echo json_encode($data); 
exit; //以json数组返回给前端 
 
function getRand($proArr) { //计算中奖概率 
    $rs = ‘‘; //z中奖结果 
    $proSum = array_sum($proArr); //概率数组的总概率精度 
    //概率数组循环 
    foreach ($proArr as $key => $proCur) { 
        $randNum = mt_rand(1, $proSum); 
        if ($randNum <= $proCur) { 
            $rs = $key; 
            break; 
        } else { 
            $proSum -= $proCur; 
        } 
    } 
    unset($proArr); 
    return $rs; 
}

?>