php按照奖品百分比随机抽奖代码分析

/**
 * 概率算法
 * @param array $probability
 * @return integer|string
 */
function get_rand($probability) {
    // 概率数组的总概率精度
    $max = array_sum($probability);
    foreach ($probability as $key => $val) {
        $rand_number = mt_rand(1, $max);//从1到max中随机一个值

        if ($rand_number  "平板电脑", "prob" => 1
    ),
    array(
        "prize" => "数码相机", "prob" => 3
    ),
    array(
        "prize" => "音箱设备", "prob" => 5
    ),
    array(
        "prize" => "8G优盘", "prob" => 20
    ),
    array(
        "prize" => "10Q币", "prob" => 200
    ),
    array(
        "prize" => "下次没准就能中噢", "prob" => 771
    )
);

foreach ($data as $key => $val) {
    $probability[$key] = $val["prob"];
}
$n = get_rand($probability);
$res['yes'] = $data[$n]["prize"];//$res['yes'] =$data[$n][0];

unset($data[$n]); // 将中奖项从数组中剔除，剩下未中奖项 
shuffle($data); // 将其它奖项顺序打乱

$func = create_function('$x', 'return $x["prize"];');

//$res['no'] = array_map(function($x){return $x[0];}, $data);  // 除了中奖外的其他数据
$res['no'] = array_map($func, $data);  // 除了中奖外的其他数据

print_r($res);