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(PHP 5)
DOMXPath::query — Evaluates the given XPath expression
$expression
[, DOMNode $contextnode
[, bool $registerNodeNS
= true
]] )
Executes the given XPath expression
.
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.
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
.
Version | Description |
---|---|
5.3.3 |
The registerNodeNS parameter was added.
|
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";
}
?>