在SimpleXML和XPath中设置父节点变量

<bookstore>
  <book>
    <title>Harry Potter</title>
    <author>J.K. Rowling</author>
  </book>
</bookstore>

$xml = simplexml_load_file('books.xml');
$book = $xml->book;
$parent = $book->parent();

<bookstore>
  <book>
    <title>Harry Potter</title>
    <author>J.K. Rowling</author>
  </book>
</bookstore>

$xml = new DOMDocument();
$xml->load('books.xml');
$xpath = new DOMXPath($xml);
$book = $xpath->query('/bookstore/book')[0];
$parent = $xpath->query('..', $book)[0];