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DOMXPath->query() DOMXPath->__construct()

Last updated: Sat, 27 Jan 2007

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# 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()

add a note User Contributed Notes
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
}
}
}
?>`
add a note
DOMXPath->query() DOMXPath->__construct()

Last updated: Sat, 27 Jan 2007
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