PHP algorithm for classifying and sorting regions

$array = array(
 0=>array("","Hebei"),
 1=>array("","Beijing"),
 2=> array(0,"Baoding"),
 3=>array(1,"Haidian"),
 4=>array(3,"Zhongguancun"),
 5=>array(2,"Zhuozhou")
);
?>

and return the following results after processing: Hebei -Baoding --Zhuozhou Beijing -Haidian --Zhongguancun

Algorithm code:

 function typeArray($array){
 $con = null;
 foreach ($array as $k=>$v){
 $na[$k] = is_numeric($ v[0]) ? $na[$v[0]].$k."|" : $k."|";
 }
 asort($na); //Sort
 foreach ($na as $k =>$v){
 $s = substr_count($v,"|");
 $con .= str_repeat("-",($s-1)).$array[$k][1]. "n";
 }
 return $con;
 }
?>