Detailed explanation of php winning algorithm

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(
&#39;0&#39; => array(&#39;id&#39;=>1,&#39;prize&#39;=>&#39;平板电脑&#39;,&#39;v&#39;=>0.1),
&#39;1&#39; => array(&#39;id&#39;=>2,&#39;prize&#39;=>&#39;数码相机&#39;,&#39;v&#39;=>5),
&#39;2&#39; => array(&#39;id&#39;=>3,&#39;prize&#39;=>&#39;音箱设备&#39;,&#39;v&#39;=>10),
&#39;3&#39; => array(&#39;id&#39;=>4,&#39;prize&#39;=>&#39;4G优盘&#39;,&#39;v&#39;=>12),
&#39;4&#39; => array(&#39;id&#39;=>5,&#39;prize&#39;=>&#39;10Q币&#39;,&#39;v&#39;=>22),
&#39;5&#39; => array(&#39;id&#39;=>6,&#39;prize&#39;=>&#39;下次没准就能中哦&#39;,&#39;v&#39;=>50),
);


foreach ($prize_arr as $key => $val) {
$arr[$val[&#39;id&#39;]] = $val[&#39;v&#39;];
}
$rid = get_rand($arr); //根据概率获取奖项id
$res[&#39;yes&#39;] = $prize_arr[$rid-1][&#39;prize&#39;]; //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][&#39;prize&#39;];
}
$res[&#39;no&#39;] = $pr;
echo json_encode($res,JSON_UNESCAPED_UNICODE);