Assuming there are no empty/blank cells in your data range...

D1 = dog
D2 = cat

Enter this array formula** in E1 and copy down to E2:

=COUNT(1/FREQUENCY(IF(A$1:A$6=D1,MATCH(B$1:B$6,B$1:B$6,0)), ROW(B$1:B$6)-MIN(ROW(B$1:B$6))+1))

** array formulas need to be entered using the key combination of
CTRL,SHIFT,ENTER (not just ENTER)


--
Biff
Microsoft Excel MVP


"Ricardo Dinis" wrote in message
...
Hi,

If I use the array formula bellow to count the unique values of a list
it works fine.

{=SUM(1/COUNTIF(C8:C11,C8:C11))}

But what I really need is the sum of unique values, of each subset of
the list.

A B
1 dog 1
2 dog 1
3 dog 3
4 dog 2
5 cat 1
6 cat 2

For example if I have the table above, the result that I want is the
sum of 3 different of dog subset elements plus 2 from cat subset.

Anyone can help me?

Thanks,

Ricardo