Converts all the lowercase characters of $string-var (a string) to their uppercase characters.
If the value of $string-var is the empty sequence, the empty sequence is returned. The empty sequence is a sequence containing zero items (), which is similar to null in SQL.
xf:lower-case(xs:string? $string-var) —> xs:string?
Returns the $string-var source string converted to lowercase characters.
Invoking lower-case("CAT") returns the string cat as shown in the following example query:
<result>{xf:lower-case("CAT")}</result>
The preceding query generates the following result:
<result>cat</result>
Invoking lower-case(()) returns the null string as shown in the following example query:
<result>{xf:lower-case(())}</result>
Note: The string: () is the empty sequence (similar to a SQL null) which is a sequence containing zero items.
The preceding query generates the following result:
<result/>
W3C lower-case function description.