Returns those items from the sequence
$seq for which the supplied function
$f returns true.
filter($seq as item()*, $f as function(item()) as xs:boolean) ➔ item()*
The sequence to be filtered
function(item()) as xs:boolean
The filtering function (used to test each item in the sequence)
Links to W3C specifications
Notes on the Saxon implementation
Available in Saxon 9.3 - 9.5 with altered argument order (
provided XPath 3.0 is enabled.