Search results
Results from the WOW.Com Content Network
XPath (XML Path Language) is an expression language designed to support the query or transformation of XML documents. It was defined by the World Wide Web Consortium (W3C) in 1999, [1] and can be used to compute values (e.g., strings, numbers, or Boolean values) from the content of an XML document.
Originally, it was based on the XPath 1.0 data model which in turn is based on the XML Information Set. The XDM consists of flat sequences of zero or more items which can be typed or untyped, and are either atomic values or XML nodes (of seven kinds: document, element, attribute, text, namespace, processing instruction, and comment).
XPath defines a syntax named XPath expressions that identifies one or more internal components (elements, attributes, etc.) of an XML document. XPath is widely used to accesses XML-structured data. The XML Information Set, or XML infoset, describes an abstract data model for XML documents in terms of information items.
Here the XPath //book is evaluated to create a sequence (aka list); the where clause is a functional "filter", the order by sorts the result, and the <shortBook>...</shortBook> XML snippet is actually an anonymous function that builds/transforms XML for each element in the sequence using the 'map' approach found in other functional languages.
XPath 3.1 [12] is an expression language that allows the processing of values conforming to the XDM [13] data model. The version 3.1 of XPath supports JSON as well as XML. jq is like sed for JSON data – it can be used to slice and filter and map and transform structured data.
XSLT 3.0 will work with either XPath 3.0 or 3.1. In the case of 1.0 and 2.0, the XSLT and XPath specifications were published on the same date. With 3.0, however, they were no longer synchronized; XPath 3.0 became a Recommendation in April 2014, followed by XPath 3.1 in February 2017; XSLT 3.0 followed in June 2017.
Compared to XPath 2.0, XPath 3.0 adds the following new features: . Inline function expressions Anonymous functions can be created in an expression context. For example, the expression function ($ a as xs:double, $ b as xs:double) as xs:double {$ a * $ b} creates a function that returns the product of its two arguments.
In HTML DOM (Document Object Model), every element is a node: [4] A document is a document node. All HTML elements are element nodes. All HTML attributes are attribute nodes. Text inserted into HTML elements are text nodes. Comments are comment nodes.