无限极分类php实现—查子孙树、家谱树

array('cat_id'=>1,'cat_name'=>'北京市','parent_id'=>0),
1=>array('cat_id'=>2,'cat_name'=>'馆陶县','parent_id'=>5),
2=>array('cat_id'=>3,'cat_name'=>'海淀区','parent_id'=>1),
3=>array('cat_id'=>4,'cat_name'=>'朝阳区','parent_id'=>1),
4=>array('cat_id'=>5,'cat_name'=>'邯郸市','parent_id'=>6),
5=>array('cat_id'=>6,'cat_name'=>'河北省','parent_id'=>0),
);


function gettree($arr,$cat_id) {
        static $list = array();
        static $num = 0;
        foreach($arr as $v) {
         echo ++$num .'
';
            if($v['cat_id'] == $cat_id) {
            	$num = 0;
                gettree($arr,$v['parent_id']);
                $list[] = $v;           
            }
        }


        return $list;
    }


$list = gettree($area,2);


print_r($list);



?>

array('cat_id'=>1,'cat_name'=>'北京市','parent_id'=>0),
1=>array('cat_id'=>2,'cat_name'=>'馆陶县','parent_id'=>5),
2=>array('cat_id'=>3,'cat_name'=>'海淀区','parent_id'=>1),
3=>array('cat_id'=>4,'cat_name'=>'朝阳区','parent_id'=>1),
4=>array('cat_id'=>5,'cat_name'=>'邯郸市','parent_id'=>6),
5=>array('cat_id'=>6,'cat_name'=>'河北省','parent_id'=>0),
);

function catsort($arr,$parent_id = 0,$lev=1) {
    static $list = array();
  	static $num = 0;
    foreach($arr as $v) {
    	echo ++$num . '
';
        if($v['parent_id'] == $parent_id) {
        	$num = 0;
            $v['lev'] = $lev;
            $list[] = $v;
            catsort($arr,$v['cat_id'],$lev+1);
        }
    }
    return $list;
}

$list = catsort($area,0,1);

foreach($list as $v) {
    echo str_repeat('    ',$v['lev']),$v['cat_name'],'
';
}

?>