Evaluates the given XPath expression

Beschreibung

public DOMXPath::query ( string $expression [, DOMNode $contextnode [, bool $registerNodeNS = TRUE ]] ) : DOMNodeList

Executes the given XPath expression.

Parameter-Liste

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.
registerNodeNS: The optional registerNodeNS can be specified to disable automatic registration of the context node.

Rückgabewerte

Returns a DOMNodeList containing all nodes matching the given XPath expression. Any expression which does not return nodes will return an empty DOMNodeList.

If the expression is malformed or the contextnode is invalid, DOMXPath::query() returns FALSE.

Changelog

Version	Beschreibung
5.3.3	The `registerNodeNS` parameter was added.

Beispiele

Beispiel #1 Getting all the english books


<?php

$doc = new DOMDocument;

// We don't want to bother with white spaces
$doc->preserveWhiteSpace = false;

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

$xpath = new DOMXPath($doc);

// We starts from the root element
$query = '//book/chapter/para/informaltable/tgroup/tbody/row/entry[. = "en"]';

$entries = $xpath->query($query);

foreach ($entries as $entry) {
    echo "Found {$entry->previousSibling->previousSibling->nodeValue}," .
         " by {$entry->previousSibling->nodeValue}\n";
}
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

Found The Grapes of Wrath, by John Steinbeck
Found The Pearl, by John Steinbeck

We can also use the contextnode parameter to shorten our expression:


<?php

$doc = new DOMDocument;
$doc->preserveWhiteSpace = false;

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

$xpath = new DOMXPath($doc);

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

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

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

foreach ($entries as $entry) {
    echo "Found {$entry->previousSibling->previousSibling->nodeValue}," .
         " by {$entry->previousSibling->nodeValue}\n";
}
?>

Siehe auch

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