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; }?>