Overview of node functions
The following table provides an overview of the so-called node functions. Some of the node functions can be called up without any argument. In this case, the function call refers to the context element.
| Signature | Description |
|---|---|
| fn:name([ $arg as node()?]) as xs:string | returns the node name as character string in the form of a |
| fn:node-name( $arg as node()?) as xs:QName? | returns the node name as expanded QName; an empty sequence is returned if no node name exists or the argument is the empty sequence |
| fn:local-name([ $arg as node()?]) as xs:string | returns the local portion of the node name as character string; an empty character string is returned if no node name exists or the argument is the empty sequence |
| fn:namespace-uri([ $arg as node()?]) as xs:string | returns the namespace portion of the node name as character string; an empty character string is returned if no node name exists, the node name does not belong to a namespace or the argument is the empty sequence |
| fn:root([ $arg as node()?]) as node()? | returns the root of the tree to which $arg belongs, or the empty sequence in case $arg is the empty sequence |
| fn:string([ $arg as item()?]) as xs:string | returns the textual value of a node; the function can also be applied to any values and returns then the same as xs:string($arg); string(()) returns the empty character string |
| fn:data([ $arg as item()*]) as xdt:anyAtomicType* | returns a sequence of atomic values, one for each element of the input sequence; if the element of the input sequence is an atomic value, it is returned unchanged, if it is a node, its typed value is returned |
| fn:number([ $arg as item()?]) as xs:double | returns xs:double($arg) in case this does not result in an error, and otherwise NaN |
Source: "XQuery – Grundlagen und fortgeschrittene Methoden", dpunkt-Verlag, Heidelberg (2004)
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