DOMXPath::query
(PHP 5, PHP 7)
DOMXPath::query — Evaluates the given XPath expression
Description
$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 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";
}
?>
See Also
- DOMXPath::evaluate() - Evaluates the given XPath expression and returns a typed result if possible
English translation
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Document created the 30/01/2003, last modified the 26/10/2018
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References
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