excel Counting unique cells Using COUNTIF()
Example
=SUMPRODUCT((A1:A100<>"")/COUNTIF(A1:A100,A1:A100&""))
counts unique cell values within A1:A100, excluding blank cells and ones with an empty string ("").
How does it do that? Example:
A1:A100 = [1, 1, 2, "apple", "peach", "apple", "", "", -, -, -, ...]
Adding &"" to the array is needed to turn blank cells (-) into empty strings (""). Result:
A1:A100&"" = ["1", "1", "2", "apple", "peach", "apple", "", "", "", "", "", ...]
After this trick, COUNTIF() can be applied. Both "" and - are counted as the same:
COUNTIF(A1:A100,A1:A100&"") = [2, 2, 1, 2, 1, 2, 94, 94, 94, 94, 94, ...]
To get the count of all unique cells, excluding blanks and "", we can divide
(A1:A100<>""), which is [1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, ...]
by our intermediate result, COUNTIF(A1:A100,A1:A100&""), and sum up over the values.
SUMPRODUCT((A1:A100<>"")/COUNTIF(A1:A100,A1:A100&""))
= (1/2 + 1/2 + 1/1 + 1/2 + 1/1 + 1/2 + 0/94 + 0/94 + 0/94 + 0/94 + 0/94 + ...)
= 4
