(PHP 5, PHP 7)
Evaluates the given XPath expression
public DOMNodeList DOMXPath::query ( string $expression [, DOMNode $contextnode [, bool $registerNodeNS = true ]] )
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.
Returns:
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
.
Changelog:
5.3.3
The registerNodeNS
parameter was added.
Examples:
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:
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