# SUMPRODUCT inside ArrayFormula

I have a fixed vector, say \$A\$1:\$E\$1

I also have a vector per row, say A2:E2, A3:E3, A4:E4...

Now I want output in Column F as

``````F2 = sumproduct(A1:E1,A2:E2)
F3 = sumproduct(A1:E1,A3:E3)
F4 = sumproduct(A1:E1,A4:E4)
...
``````

Now I want to put these into one array formula, but I don't know how to do it. For example

``````F2 = Arrayformula(sumproduct(\$A\$1:\$E\$1,A2:A:E2:E))
``````

Meaning multiply A1-E1 vector with A2:E2, then A3:E3 and so on.

How do I do this?

## 1 Answer

``````=ARRAYFORMULA(IF(LEN(A2:A&B2:B&C2:C&D2:D&E2:E),
MMULT(A1:E1*A2:E,TRANSPOSE(COLUMN(A1:E1)^0)), ))`````` • Thank you. I'm having a bit trouble parsing the formula but seems to work. – Paul May 24 '19 at 14:59
• I have played around with this "=A2:A&B2:B&C2:C" and I have no idea what it does. It just gets some of the cells as a string but for a life of me it seems so random what cells it gets. Can you clarify? And then Length of that, ok. But then IF that length? What does that do? – Paul May 24 '19 at 15:09
• COLUMN(A1:E1) just returns a single digit of the column, that to ^0 is then just always "1" isn't it? – Paul May 24 '19 at 15:17
• can you share a copy of your sheet? – user0 May 24 '19 at 16:24
• link The cell I wanted to put this into is idx!AB12 The fixed vector is idx!P8:AA8 and the row of vectors is idx!D12:D ... O12:O – Paul May 24 '19 at 21:01