Using XPath to Retrieve Node Information - PHP

XPath is a W3C standard that offers an intuitive, path-based syntax for identifying XML nodes. For example, referring to thebooks.xmldocument, you could use thexpath()method to retrieve allauthornodes using the expression/library/book/author:

array simplexml_element->xpath(string path)

XPath also offers a set of functions for selectively retrieving nodes based on value.

Suppose you want to retrieve all authors found in thebooks.xmldocument:

<?php
    $xml = simplexml_load_file("books.xml");
    $authors = $xml->xpath("/library/book/author");
    foreach($authors AS $author) {
        echo "$author<br />";
    }
?>

This example returns the following:

--------------------------------------------
Jane Austen
Alberto Moravia
Ernest Hemingway
--------------------------------------------

You can also use XPath functions to selectively retrieve a node and its children based on a particular value. For example, suppose you want to retrieve allbooktitles where the author is namedErnest Hemingway:

This example returns the following:

--------------------------------------------
The Sun Also Rises
--------------------------------------------