XSLT, 2nd Edition

Name

key()

References a relation defined with an <xsl:key> element. Conceptually, the key() function works similarly to the id() function, although keys are more flexible than IDs.

Syntax

[1.0] node-set key(string, object)
[2.0] node()* key(xs:string, xs:anyAtomicType*)
[2.0] node()* key(xs:string, xs:anyAtomicType*, node())

Inputs

[1.0] The name of the key (defined by an <xsl:key> element) and an object. If the object is a node-set, then the key() function applies itself to the string value of each node in the node-set and returns the node-set of the result of all those key() function invocations. If the object is any other type, it is converted to a string as if by a call to the string() function.

[2.0] The name of the key (an xs:string) and a sequence of search values. An optional third argument limits the search to all the nodes that have the specified node as an ancestor-or-self node. The third argument lets us limit the search results to a particular group of nodes.

Output

[1.0] A node-set containing the nodes in the same document as the context node whose values for the requested key match the search argument(s). In other words, if our stylesheet has an <xsl:key> element that defines a key named postalcodes based on the <postalcode> child of all <address> elements in the current document, the function call key(postalcodes, '34829') returns a node-set containing all the <address> elements with a <postalcode> element whose value is 34829.

[2.0] A sequence of nodes, each of which matches ...