(PHP 5 >= 5.3.0)
SimpleXMLElement::count — Counts the children of an element
This method counts the number of children of an element.
Returns the number of elements of an element.
Beispiel #1 Counting the number of children
<?php
$xml = <<<EOF
<people>
 <person name="Person 1">
  <child/>
  <child/>
  <child/>
 </person>
 <person name="Person 2">
  <child/>
  <child/>
  <child/>
  <child/>
  <child/>
 </person>
</people>
EOF;
$elem = new SimpleXMLElement($xml);
foreach ($elem as $person) {
    printf("%s has got %d children.\n", $person['name'], $person->count());
}
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
Person 1 has got 3 children. Person 2 has got 5 children.
I used the DOMNodeList $length property to simulate this function since my host had not yet implemented PHP 5.3.  The following code makes it portable and allows you to prepare for an upgrade path.
<?php
$url = "http://www.example.com/foo.xml";
$xml = simplexml_load_file($url);
// For debugging
// echo "<p>".phpversion()."</p>";
if(phpversion() >= '5.3.0'){
    $bar_count = $xml->foo->bar->count();
    }
else    {
    $doc = new DOMDocument();
    $str = $xml->asXML();
    $doc->loadXML($str);
    $bar_count = $doc->getElementsByTagName("bar")->length;
    }
echo "There are ".$bar_count." \"bar\" nodes in this document.<br />";
?>