In article , says...

John Black;1606387 Wrote:
In article ,
says...-


=SUMPRODUCT(1/COUNTIF(A1:A4,A1:A4))-

I don't really get how this works?

John Black

It sum 1 for every single string, 1/2 for every double string, 1/3 for
every triple string, and so on.
So that the sum report the total number of different strings.

Thanks, that's clever. But I found many descriptions of COUNTIF on the web but I still can't
figure out what it means to have the condition field be a range of cells?

John Black

That formula reports the matrix formed by every single result obtained using every cell of the range.

(1/COUNTIF(A1:A4,A1))+(1/COUNTIF(A1:A4,A2))+(1/COUNTIF(A1:A4,A3))+(1/COUNTIF(A1:A4,A4))

E.

John,

In the case of SUMPRODUCT, the arguments are arrays. So even though COUNTIF only looks at one condition at a time, SUMPRODUCT will go through each cell in the array. You could think about it as though the formula was written as an array formula this way:

{=SUM(1/COUNTIF(A1:A4, A1:A4))}

Excel would look at the array above and translate it as:

1/COUNTIF(A1:A4, A1) +
1/COUNTIF(A1:A4, A2) +
1/COUNTIF(A1:A4, A3) +
1/COUNTIF(A1:A4, A4)

It might be easiest to see how the function works by using the "Evaluate Formula" button on the Formulas tab to step through the calculations one at a time.

Ben