PHP 連想配列並び替え

$arr = array('T'=>'Tokyo', 'Y'=>'Yokohama', 'K'=>'Kyoto');
$arr += array('N'=>'Nagoya');
$arr2 = array('N','K','Y','T');//連組配列を並び替える
$ret=array();
foreach ($arr2 as $key => $value) {
 foreach ($arr as $k => $v) {
 if($value===$k){
  switch ($k) {
   case 'N':
    $ret=array_merge($ret,array($k => 'なごや'));
    break;
   
   default:
    $ret=array_merge($ret,array($k => $v));
    echo '
';
    var_dump($ret);
    echo '
';

    break;
  }  
 }
 }
}