无限分类

/**
*参    数：$list 分类数据 $pid父id
*功    能：无限级分类
*/

function Tree(&$list , $pid = 0 , $level = 0 , $html = '--')
{
static $tree = array();
foreach($list as $v)
{
if($v['parent_did'] == $pid)
{
$v['level'] = $level;
$v['html'] = str_repeat($html, $level);
$tree[] = $v;
Tree($list, $v['did'], $level + 1, $html);
}
}
return $tree;
}

$area = array(
array('did'=>1,'name'=>'安徽','parent_did'=>0),
array('did'=>2,'name'=>'合肥','parent_did'=>1),
array('did'=>3,'name'=>'枞阳','parent_did'=>5),
array('did'=>4,'name'=>'浦东','parent_did'=>7),
array('did'=>5,'name'=>'安庆','parent_did'=>1),
array('did'=>6,'name'=>'杨浦','parent_did'=>7),
array('did'=>7,'name'=>'上海','parent_did'=>0),
array('did'=>8,'name'=>'肥东','parent_did'=>2),
array('did'=>9,'name'=>'唐镇','parent_did'=>4)
);
$tree = Tree($area,0,1);