DOMXPath::evaluate

(PHP 5 >= 5.1.0, PHP 7)

DOMXPath::evaluate — Evaluates the given XPath expression and returns a typed result if possible

Beschreibung

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

Executes the given XPath expression and returns a typed result if possible.

Parameter-Liste

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.

Rückgabewerte

Returns a typed result if possible or a DOMNodeList containing all nodes matching the given XPath expression.

If the expression is malformed or the contextnode is invalid, DOMXPath::evaluate() returns FALSE.

Beispiele

Beispiel #1 Getting the count of all the english books

<?php

$doc = new DOMDocument;

$doc->load('book.xml');

$xpath = new DOMXPath($doc);

$tbody = $doc->getElementsByTagName('tbody')->item(0);

// our query is relative to the tbody node
$query = 'count(row/entry[. = "en"])';

$entries = $xpath->evaluate($query, $tbody);
echo "There are $entries english books\n";

?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

There are 2 english books

Siehe auch