Evaluates the given XPath expression

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- PHP Manual
- DOMXPath
- Evaluates the given XPath expression

# DOMXPath::query

(PHP 5, PHP 7, PHP 8)

DOMXPath::query — Evaluates the given XPath expression

### Description

public DOMXPath::query(string `$expression`, ?DOMNode `$contextNode` = `null`, bool `$registerNodeNS` = `true`): mixed

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