DOMXPath->evaluate()

(No version information available, might be only in CVS)

DOMXPath->evaluate() — Evaluates the given XPath expression and returns a typed result if possible.

说明

DOMXPath

mixed evaluate ( string $expression [, DOMNode $contextnode ] )

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

参数

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.

返回值

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

范例

Example#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";

?>

上例将输出：

There are 2 english books

参见

DOMXPath->query()