Php/docs/domxpath.query
DOMXPath::query
(PHP 5, PHP 7)
DOMXPath::query — Evaluates the given XPath expression
Description
public DOMXPath::query
( string $expression
[, DOMNode $contextnode
[, bool $registerNodeNS
= TRUE
]] ) : DOMNodeList
Executes the given XPath expression
.
Parameters
expression
- The XPath expression to execute.
contextnode
- The optional
contextnode
can be specified for doing relative XPath queries. By default, the queries are relative to the root element. registerNodeNS
- The optional
registerNodeNS
can be specified to disable automatic registration of the context node.
Return Values
Returns a DOMNodeList containing all nodes matching
the given XPath expression
. Any expression which
does not return nodes will return an empty
DOMNodeList.
If the expression
is malformed or the
contextnode
is invalid,
DOMXPath::query() returns FALSE
.
Examples
Example #1 Getting all the english books
<?php$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