Converting arrays into UDFs

[mr_targ]

Hi there - I'm a new member of the forum, and trying to get my head around transferring arrays into UDFs, so that I can invoke some functions instead of littering an excessively complex workbook with absurdly long arrays.

For example, I’m trying to convert the following string (with declared ranges) into a VBA UDF:<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
<o> </o>
=SUM(IF(FcastWPs=[argument],IF(FcastDates>LastUpdate,IF(FcastDates<[argument],FcastAllData)*FcastRates)))

Any help would be immensely appreciated!

Thanks,

Targ