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. Available for all platforms.