DOMXPath::query
(PHP 5, PHP 7, PHP 8)
DOMXPath::query — Evaluates the given XPath expression
Description
$expression, ?DOMNode $contextNode = null, bool $registerNodeNS = true): mixed
Executes the given XPath expression.
Parameters
-
expression -
The XPath expression to execute.
-
contextNode -
The optional
contextNodecan be specified for doing relative XPath queries. By default, the queries are relative to the root element. -
registerNodeNS -
The optional
registerNodeNScan be specified to disable automatic registration of the context node.
Return Values
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.
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 start 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";
}
?>
See Also
- DOMXPath::evaluate() - Evaluates the given XPath expression and returns a typed result if possible
