PHP抽奖程序概率算法

//概率算法,6个奖项 $prize_arr = array( '0' => array('id'=>1,'prize'=>'iphone6','v'=>1), '1' => array('id'=>2,'prize'=>'数码相机','v'=>5), '2' => array('id'=>3,'prize'=>'音箱设备','v'=>10), '3' => array('id'=>4,'prize'=>'50Q币','v'=>24), '4' => array('id'=>5,'prize'=>'10Q币','v'=>60), '5' => array('id'=>6,'prize'=>'1Q币','v'=>1900), ); //每个奖品的中奖几率,奖品ID作为数组下标 foreach($prize_arr as $val){ $item[$val['id']] = $val['v']; } function get($item){ //中奖概率基数 $num = array_sum($item);//当前一等奖概率1/2000 foreach($item as $k=>$v){ //获取一个1到当前基数范围的随机数 $rand = mt_rand(1,$num); if($rand <= $v){ //假设当前奖项$k=2,$v1900,则没中六等奖,总获奖基数2000-1900,前五次循环都没中则2000-1-5-10-24-60=1900,必中6等奖,哈哈 $num -= $v; } } return $res; } $res = get($item); $h = $prize_arr[$res-1]['prize']; echo $h.'; ';