About XPath

XPath is a notation for retrieving information from a document. The information could be a set of nodes or derived values.

XPath allows you to identify parts of an XML document. In addition, a subset of XPath allows you to test whether or not a node matches a particular pattern. XPath provides Boolean logic, filters, indexing into collections of nodes, and more.

XPath is declarative rather than procedural. You use a pattern modeled on directory notation to describe the types of nodes to look for. For example, book/author means find all author elements that are contained in book elements.

XPath provides a common syntax for features shared by Extensible Stylesheet Language Transformations (XSLT) and XQuery. XSLT is a language for transforming XML documents into XML, HTML, or text. XQuery builds on XPath and is a language for extracting information from XML documents.

The basic syntax for XPath mimics the Uniform Resource Identifier (URI) directory navigation syntax. However, the syntax does not specify navigation through a physical file structure. The navigation is through elements in the XML tree.