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PHP Dokumentation: Domxpath query

12. Januar 2010 von werner

DOMXPath::query

(PHP 5)

DOMXPath::query — Evaluates the given XPath expression

Beschreibung

DOMNodeList DOMXPath::query ( string $expression [, DOMNode $contextnode ] )

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.

Rückgabewerte

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

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 folgendeAusgabe:

Found The Grapes of Wrath, by John SteinbeckFound 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"; } ?>