DOMXPath::query

(PHP 5, PHP 7)

DOMXPath::query Evaluates the given XPath expression

Descrierea

public DOMXPath::query ( string $expression [, DOMNode $contextnode [, bool $registerNodeNS = TRUE ]] ) : DOMNodeList

Executes the given XPath expression.

Parametri

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.

Valorile întoarse

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.

Istoricul schimbărilor

Versiune Descriere
5.3.3 The registerNodeNS parameter was added.

Exemple

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";
}
?>

Exemplul de mai sus va afișa:

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";
}
?>

A se vedea și

  • DOMXPath::evaluate() - Evaluates the given XPath expression and returns a typed result if possible