I've a custom formula that basically looks up a string of array data based on user input to find the correct result. I'm needing to develop this so that instead of a series for each year there will be three.

At the moment the formula uses case to detect the year and point at the correct array. For the new version what I had hoped to do was concatenate enough info the construst the name fo the array that is to be looked up. So stripping out the unnecessary stuff:

Function Test(var1,var2,var3)
TIndex=var1/5
rates2013_quarter=Array(list of info)

refer_to=var2 & "_" & var3

Test=refer_to(TIndex)
Hopefully that makes sense. I've also tried adding the text "(TIndex)" to the refer_to variable, but the formula still refuses to work. The concatenation is fine for sure - as that happens to be the result if I add (TIndex) to the string.

Is what I'm trying to do even possible? If so what am I doing wrong?

Thanks in advance.