XPath (XML Path Language) is a language for selecting nodes from within an XML document. Version 1.0 of the XPath standard was released in 1999, and is now supported in most languages and platforms.
Version 2.0 of the standard was released in 2007 in an effort to share more functionality between the XSLT and XQuery standards. Version 2.0 is backwardly compatible with 1.0 and adds a number new operators including looping, set manipulation, conditional expression, and aggregate functions.
TheXPath Expression Builder included in Liquid XML Studio makes it simple to visualize the results of your XPath Expressions.
<?xml version="1.0" encoding="utf-8"?>
<Catalog>
<Album artist="The Last Shadow Puppets" title="The Age Of The Understatement">
<Track rating="4" length="P3M7S">The Age Of The Understatement</Track>
<Track rating="3" length="P2M18S">Standing Next To Me</Track>
<Track rating="5" length="P2M26S">Calm Like You</Track>
<Track rating="3" length="P3M38S">Separate and Ever Deadly</Track>
<Track rating="2" length="P2M37S">The Chamber</Track>
<Track rating="3" length="P2M44S">Only The Truth</Track>
</Album>
<Album artist="Kings Of Leon" title="Because Of The Times">
<Track rating="4" length="P7M10S">Knocked Up</Track>
<Track rating="2" length="P2M57S">Charmer</Track>
<Track rating="3" length="P3M21S">On Call</Track>
<Track rating="4" length="P3M09S">McFearless</Track>
<Track rating="1" length="P3M59S">Black Thumbnail</Track>
</Album>
</Catalog>