PHP 无限级分类(递归)

网上有很多,这是我自己做测试用的

$arr = array(
    array('id'=>1,'name'=>'电脑','pid'=>0),
    array('id'=>2,'name'=>'手机','pid'=>0),
    array('id'=>3,'name'=>'笔记本','pid'=>1),
    array('id'=>4,'name'=>'台式机','pid'=>1),
    array('id'=>5,'name'=>'智能机','pid'=>2),
    array('id'=>6,'name'=>'功能机','pid'=>2),
    array('id'=>7,'name'=>'超级本','pid'=>3),
    array('id'=>8,'name'=>'游戏本','pid'=>3),
);

/**
 * @param $arr 数组
 * @param $id   id
 * @param $level  层级
 * @return array
 */

function demo($arr,$id,$level)
{
    $list =array();
    foreach ($arr as $k=>$v){
        if ($v['pid'] == $id){
            $v['level']=$level;
            $v['son'] = demo($arr,$v['id'],$level+1);
            $list[] = $v;
        }
    }
    return $list;
}
echo "<pre>";
print_r(demo($arr,0,0));

输出结果:

Array
(
    [0] => Array
        (
            [id] => 1
            [name] => 电脑
            [pid] => 0
            [level] => 0
            [son] => Array
                (
                    [0] => Array
                        (
                            [id] => 3
                            [name] => 笔记本
                            [pid] => 1
                            [level] => 1
                            [son] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 7
                                            [name] => 超级本
                                            [pid] => 3
                                            [level] => 2
                                            [son] => Array
                                                (
                                                )

                                        )

                                    [1] => Array
                                        (
                                            [id] => 8
                                            [name] => 游戏本
                                            [pid] => 3
                                            [level] => 2
                                            [son] => Array
                                                (
                                                )

                                        )

                                )

                        )

                    [1] => Array
                        (
                            [id] => 4
                            [name] => 台式机
                            [pid] => 1
                            [level] => 1
                            [son] => Array
                                (
                                )

                        )

                )

        )

    [1] => Array
        (
            [id] => 2
            [name] => 手机
            [pid] => 0
            [level] => 0
            [son] => Array
                (
                    [0] => Array
                        (
                            [id] => 5
                            [name] => 智能机
                            [pid] => 2
                            [level] => 1
                            [son] => Array
                                (
                                )

                        )

                    [1] => Array
                        (
                            [id] => 6
                            [name] => 功能机
                            [pid] => 2
                            [level] => 1
                            [son] => Array
                                (
                                )

                        )

                )

        )

)