多维PHP数组怎么转换成xml格式的数据

 $ar=array
( 
	"auth"=> array 
	(
		"user"=>  "customer" ,
		"password"=>  "password" ,
		"context"=>  "4" 
	) ,
	"owner"=> array 
	( 
		"user"=>  "customer2" ,
		"context"=>  "4" 
	) ,
	"language"=>  "en" ,
	"task"=> array
	( 
		"code"=>  "0130" 
	) 
);


$doc = new DOMDocument('1.0','UTF-8');
// we want a nice output
$doc->formatOutput = true;

$root = $doc->createElement('request');
$root = $doc->appendChild($root);

 foreach($ar as $title=>$title_v){
   $title = $doc->createElement($title);
   $title = $root->appendChild($title); 
    if(is_array($title_v)){
       foreach($title_v as $k=>$v){
	       $k = $doc->createElement($k);
           $k = $title->appendChild($k);
		   $text = $doc->createTextNode($v);
           $text = $k->appendChild($text);
	   } 
   }else{
       $text = $doc->createTextNode($title_v);
       $text = $title->appendChild($text);
   }
}

echo $doc->saveXML();

$ar = array( 
	"auth" => array( 
		"user" => "customer",
		"password" => "password",
		"context" => "4",
	),
	"owner" => array( 
		"user" => "customer2",
		"context" => "4",
	),
	"language" => "en",
	"task" => array( 
		"code" => "0130",
	), 
);
$xml = simplexml_load_string('');
create($ar, $xml);
echo $xml->saveXML();

function create($ar, $xml) {
	foreach($ar as $k=>$v) {
		if(is_array($v)) {
			$x = $xml->addChild($k);
			create($v, $x);
		}else $xml->addChild($k, $v);
	}
}

 


customer 
password 
4 


customer2 
4 

en 

0130