1.抽奖

2.核心算法
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;
}











