Last cell in an array

[Stas]

Hi all and thanks in advance for considering this:

I have a matrix of mubers (It is made up of arrays of numbers going across rows)
some of these arrays are full of numbers, yet others have blanks in them.
I use this to count the number of values in these arrays:
=COUNT(INDEX(rawrets,MATCH(C34,rawnames,0)-6,0))

C34 in this case contains the name of the array and the 0 indicates taht it should return the whole array.

Now the question:

Is it possible in excel to write a function that returns the INDEX of the LAST or FIRST non-blank element in an array?

For instance, i want to know where the data ends in my array rawrets[15,0]
How would I do that??

Thanks a lot in advance!

Stan