Find a node with xpath - php

Question

I'd like to parse google geocode api respond, but the structure of the result is not always the same. I need to know the postal code for example, but it is sometimes in the Locality/DependentLocality/PostalCode/PostalCodeNumber node and sometimes in the Locality/PostalCode/PostalCodeNumber node. I don't really know the logic behind this, just want to get the value of the PostalCodeNumber node, no matter where is it exactly. Can I do it with XPath? If so, how?
UPDATE
Tried with //PostalCodeNumber but it returns an empty array. The code snippet is the following:
$xml = new \SimpleXMLElement($response);
var_dump($xml->xpath('//PostalCodeNumber'));
The $response is the content of http://maps.google.com/maps/geo?q=1055+Budapest&output=xml
(copy paste the url instead of clicking on it because of some character problems...)

Answer 1

Try to use this XPath:
Locality//PostalCodeNumber
It will find all descendants PostalCodeNumber of Locality element.

Answer 2

//PostalCode/PostalCodeNumber
Should do the trick. A quick google search yields the following schema snippet, indicating that there may be multiple DependentLocality elements, nested, so you'll want to check for multiple results, and have some idea of whether you want the most specific (most deeply nested) or least specific.
Update:
To guard against namespace issues, explicitly add the namespace to the query:
$xml = new SimpleXMLElement($response);
$xpath->registerXPathNamespace('ns', 'urn:oasis:names:tc:ciq:xsdschema:xAL:2.0');
var_dump($xml->xpath('//ns:PostalCodeNumber'));
Update 2: fixed a couple of typos
Update 3:
<?php
$result = file_get_contents('http://maps.google.com/maps/geo?q=1055+Budapest&output=xml');
$sxe = new SimpleXMLElement($result);
$sxe->registerXPathNamespace('c', 'urn:oasis:names:tc:ciq:xsdschema:xAL:2.0');
$search = $sxe->xpath('//c:PostalCodeNumber');
foreach($search as $code) {
echo $code;
}
?>