(PHP 5, PHP 7, PHP 8)
DOMXPath::query — Evaluates the given XPath expression
$expression
, ?DOMNode $contextNode
= null
, bool $registerNodeNS
= true
): mixed
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
Визначає, чи необхідно автоматично реєструвати префікси простору імен в області видимості контекстного вузла для об'єкта DOMXPath. Потрібно для того, щоб не викликати метод DOMXPath::registerNamespace() для кожного простору імен в області видимості. Коли префікси збігаються, реєструється тільки префікс простору імен найближчого нащадка.
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
.
The following errors are possible when using an expression that invokes PHP callbacks.
Приклад #1 Getting all the english books
<?php
$doc = new DOMDocument;
// We don't want to bother with white spaces
$doc->preserveWhiteSpace = false;
$doc->load('examples/book-docbook.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";
}
?>
Поданий вище приклад виведе:
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('examples/book-docbook.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";
}
?>