DOMXPath->evaluate()

Evaluates the given XPath expression and returns a typed result if possible. ()

DOMXPath {
  mixed evaluate(string expression,
                 DOMNode contextnode);
}

Executes the given XPath expression and returns a typed result if possible.

Parameters

expression: The XPath expression to execute.
contextnode: The optional contextnode can be specified for doing relative XPath queries. By default, the queries are relative to the root element.

Return Values

Returns a typed result if possible or a DOMNodeList containing all nodes matching the given XPath expression.

Examples

Example 544. Getting the count of all the english books

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<?php


$doc = new DOMDocument;

$doc->load('book.xml');

$xpath = new DOMXPath($doc);

$tbody = $doc->getElementsByTagName('tbody')->item(0);

// our query is relative to the tbody node
$query = 'count(row/entry[. = "en"])';

$entries = $xpath->evaluate($query, $tbody);

echo "There are $entries english books\n";

?>

The above example will output:

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There are 2 english books

See Also

DOMXPath->query()

Code Examples / Notes » dom_domxpath_evaluate

yuriucsal

this class can substitute the method evaluate while it is not validated. Made for Yuri Bastos and João Gilberto Magalhães. <?php class XPtahQuery { // function returns a DOMNodeList from a relative xPath public static function selectNodes($pNode, $xPath) { $pos = strpos(self::getFullXpath($pNode),"/",1); $xPathQuery = substr(self::getFullXpath($pNode),$pos);//to paste /#document[1]/ $xPathQueryFull = $xPathQuery. $xPath; $domXPath = new DOMXPath($pNode->ownerDocument); $rNodeList = $domXPath->query($xPathQueryFull); return $rNodeList; } // function returns a DOMNode from a xPath from other DOMNode public static function selectSingleNode($pNode, $xPath) { $pos = strpos(self::getFullXpath($pNode),"/",1); $xPathQuery = substr(self::getFullXpath($pNode),$pos);//to paste /#document[1]/ $xPathQueryFull = $xPathQuery. $xPath; $domXPath = new DOMXPath($pNode->ownerDocument); $rNode = $domXPath->query($xPathQueryFull)->item(0); return $rNode; } //utilitaries functions off selectSingleNode private function getNodePos($pNode, $nodeName) { if($pNode == null) { return 0; } else { $var = 0; if ($pNode->previousSibling != null) { if ($pNode->previousSibling->nodeName == $nodeName) { $var = 1; } } return self::getNodePos($pNode->previousSibling, $nodeName) + $var; } } //utilitaries functions off selectSingleNode private function getFullXpath($pNode) { if($pNode == null) { return ""; } else { return self::getFullXpath($pNode->parentNode) . "/" . $pNode->nodeName . "[" .strval(self::getNodePos($pNode, $pNode->nodeName)+1) . "]";//+1 to get the real xPath index } } } ?>