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.
說明
DOMXPath
mixed evaluate
( string $expression
[, DOMNode $contextnode
] )
Executes the given XPath expression and returns a typed result if possible.
參數
- 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.
Return值
Returns a typed result if possible or a DOMNodeList containing all nodes matching the given XPath expression .
範例
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";
?>
上例將輸出：
There are 2 english books