 | This article includes alist of references,related reading, orexternal links,but its sources remain unclear because it lacksinline citations. Please helpimprove this article byintroducing more precise citations.(December 2022) (Learn how and when to remove this message) |
XPath 3 is the latest version of theXML Path Language, aquery language for selecting nodes inXML documents. It supersedesXPath 1.0 andXPath 2.0.
XPath 3.0 became aW3C Recommendation on 8 April 2014, whileXPath 3.1 became aW3C Recommendation on 21 March 2017.
Compared toXPath 2.0, XPath 3.0 adds the following new features:
function($aasxs:double,$basxs:double)asxs:double{$a*$b} creates a function that returns the product of its two arguments. The expressioncollection()/(let$a:=.returnfunction(){$a}) creates a sequence of functions, each one returning a different node from a collection.$f[2]("Hi there") fetches the second item from sequence$f, and invokes it as a function, passing the string"Hi there" as argument.math:pi may be expanded toQ{http://www.w3.org/2005/xpath-functions/math}pi, embedding the namespace URI inside the prefix.||operator may be used forstring concatenation:$a || $b is equivalent tofn:concat($a,$b).! operator performs simple mapping:E1 ! E2 evaluatesE2 for each item in the sequenceE1, and concatenates the resulting items. This is comparable to the path operator/, but the! operator does not perform duplicate elimination nor document ordering of the results.XPath 3.1 mainly adds support forarray and map (associative array) data types. These types and their associated functionality are intended to ease working withJSON data.
Another innovation is the arrow operator=> for function chaining. For example, the XPath 2.0 expression
contains(upper-case(substring-before($in,' ')),'X')
can now be written
$in=>substring-before(' ')=>upper-case()=>contains('X')
 | This computing article is astub. You can help Wikipedia byadding missing information. |