Gary's student-

I tried as well using the following (less complex for my brain) function.
I'm not guru, but my best guess is that initially you are feeding in a range
of one cell, so it can handle it accordingly. When you pass it a larger
range in the sumproduct formula, your prime formula is taking the whole
range at once instead of each cell one at a time. I haven't found it yet,
but I wonder if there is a way to make your prime function's parameter a
range of a single cell size only?

'my shortened function below

Function prime(r As Range) As Variant
primenums = Array(1, 2, 3, 5, 7, 11, 13, 17, 19, 23)

If IsError(Application.Match(r.Value, primenums, False)) Then
'no match
prime = False
Else
'matches a number in the primenums array
prime = True

End If

End Function

"Gary''s Student" wrote in message
...
I am trying to use a UDF within a SUMPRODUCT formula, but am having a
problem
getting the UDF to correctly return an array. Simplified data in A1 thru
B24:

23 1
14 2
16 2
9 1
21 2
10 2
20 1
17 3
13 1
15 1
22 3
8 3
2 1
19 1
3 1
1 2
4 2
11 3
6 2
18 2
5 3
7 2
12 1
24 3

I need to count the number of rows in which the value in column A is prime
and the value in column B is 3. The values in column A are always 25 or
less. My sad attempt at a UDF is:

Function prime(r As Range) As Variant
pm = Array(1, 2, 3, 5, 7, 11, 13, 17, 19, 23)
Dim v() As Variant
ReDim v(1 To r.Count)
j = 1
For Each rr In r
x = rr.Value
v(j) = 0
For i = 0 To 9
If x = pm(i) Then
v(j) = 1
End If
Next
j = j + 1
Next
prime = v
End Function

The function should return a 1 if the argument is prime, otherwise 0.

The function works for single items like:
=prime(A1)
The function also works within SUMPRODUCT like:
=SUMPRODUCT(--(prime(A1:A24)=1))

The function, however, returns #VALUE!
for:
=SUMPRODUCT(--(prime(A1:A24)=1),--(B1:B24=3))

(I usually get this if the sumproduct inputs are of different lengths)

This is not urgent since I can use a helper column until I can get
sumproduct to work.

Thanks in advance for any help.
--
Gary''s Student - gsnu200797