PHP: DOMXPath->evaluate()

DOMXPath->evaluate()

(no version information, might be only in CVS)

DOMXPath->evaluate() -- Evaluates the given XPath expression and returns a typed result if possible.

Описание

class DOMXPath {

mixed evaluate ( string expression [, DOMNode contextnode] )

}

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

Список параметров

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.

Возвращаемые значения

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

Примеры

Пример 1. Getting the count of all the english books

<?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"; ?>
Результат выполнения данного примера:
There are 2 english books

Смотрите также

DOMXPath->query()

DOMXPath->evaluate()

yuriucsal at NOSPAM dot yahoo dot com dot br
06-Mar-2005 12:55


this class can substitute the method evaluate while it is not validated. Made for Yuri Bastos and Jo�o Gilberto Magalh�es. 



<?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



            }

        }

    }

?>

ernest at vogelsinger dot at
23-Jan-2005 10:54


The DOMXPath::evaluate() method will not be available before v.5.1 (see bug database #31593). Only query() is available, which cannot evaluate all XPath expressions,such as count() or not().