fn:zero-or-one
Tests whether a given sequence contains zero or one items; fails if it contains multiple items.
zero-or-one($arg as item()*) ➔ item()?
Arguments | |||
| $arg | item()* | The input sequence to be tested |
Result | item()? | ||
Namespace
http://www.w3.org/2005/xpath-functions
Links to W3C specifications
XPath 3.1 Functions and Operators
Saxon availability
Available in XPath 2.0, XSLT 2.0, XQuery 1.0, and later versions. Available in all Saxon editions.