I have in my Main report a formula using the following code:

stringVar Segments;
WhileReadingRecords;
Segments:=Segments + ({TableA.ColumnX}) + ","

This gives me an array something like Value1,Value2,etc. There may be any number of values, including none, 1, 2, or 3.

So in my subreport I have created another formula field of the same name (Segments) and pass in {?Pm-@Segments}, having previously linked the subreport to the main report via @Segments. If I display this in my subreport it gives me exactly what I expect - i.e. Value1,Value2,etc.

Now I need to extract each array element as an individual string so that I can use them in my record selection formula. For example, another Formula field using split({?Pm-@Segments},",")[1]

This works and returns the first string. However, I need to add a test to see if the array element really exists and if not substitute with some other text to avoid a run-time error.

So why does this not work:
if ubound({?Pm-@Segments}) = 3 then split({?Pm-@Segments},",")[1] else "N/A"

The argument for the Ubound function returns an error "An array is required here", yet the Split function deals only with arrays???

How can I perform this test on all my array elements?