php如何取取xml里的数据

$doc = new DomDocument();
$doc->load("file.xml"); 
$lists=$doc->getElementsByTagName("list");
foreach($lists as $list){
      $path=$list->getAttribute("path"); 
      $smallinfo=$list->getAttribute("smallinfo"); 
     $arr[]=array('path'=>$path,'smallinfo'=>$smallinfo,'url'=>$list->nodeValue);
}
print_r($arr);