DOMXPath::query

(PHP 5)

DOMXPath::query — Evaluates the given XPath expression

Description

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

Executes the given XPath expression .

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

Examples

Example #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";
}
?>

The above example will output:

  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";
}
?>

DOMXPath::query

Description

Parameters

Return Values

Examples

See Also