XPath

XPath, which stands for [[Extensible Markup Language|XML]] Path Language, is a query language that allows for the selection of nodes from an XML document. It's a critical technology in the realm of XML data handling, enabling the extraction and manipulation of data from XML documents.

XPath is primarily used to select nodes from an XML document. These nodes can be elements, attributes, text, and more. XPath expressions allow for navigating through elements and attributes in an XML document.

XPath uses a path-like notation for navigating through the hierarchical structure of an XML document. For example, /bookstore/book selects all book elements that are children of bookstore

XPath is used in various XML-related technologies, including [[XSLT (Extensible Stylesheet Language Transformations)]], [[XQuery]], and [[XML Schema]].

XPath supports conditional selections using predicates. For example, /bookstore/book[price>35.00] selects all book elements in bookstore that have a price element with a value greater than 35.

XPath includes functions for string values, numeric values, date and time comparison, node and QName manipulation, sequence manipulation, Boolean values, and more. XPath defines several data types such as node-set, string, number, and Boolean. XPath expressions evaluate to one of these data types.

There are multiple versions of XPath; XPath 1.0 and XPath 2.0 are the most commonly used. XPath 2.0 is more powerful and includes additional functions and capabilities. XPath expressions are often used within XSLT for defining transformations and within XQuery for querying XML data.

XPath supports XML namespaces. This is important for querying XML documents that use namespace prefixes.