DOMXPath->evaluate()
DOMXPath->evaluate() -- 
   Evaluates the given XPath expression and returns a typed result if possible.
  
Description
class 
DOMXPath { 
mixed 
evaluate ( string expression [, DOMNode contextnode] )
}
   Executes the given XPath expression and returns
   a typed result if possible.
  
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.
       
Return Values
   Returns a typed result if possible or a DOMNodeList 
   containing all nodes matching the given XPath expression. 
  
Examples
   
| 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";
 
 ?>
 | 
 The above example will output: | There are 2 english books | 
 |