在电子表格中查找每一行的总和

Question

I'm new to Sheets and I don't know any terminology yet so I wasn't sure how to look this up. If I have:

A1[=SUM(B1:1)]

How do I automatically copy that to A2 so that:

A2[=SUM(B2:2)]

And the same thing continues either indefinitely or until I declare a stopping point?

Answer 1

First of all, if you simply copy-paste the formula from A1 to A2 (or several cells below), it will automatically change as you want. This is how relative references work.

But it's also possible to get all the sums with one formula. The following formula, entered in A1, will create sums of the first seven row in column A. To change the number of rows summed, replace 7 in B1:7 with another number.

=arrayformula(mmult(B1:7 + 0, transpose(B1:1 * 0 + 1)))

Explanation:

• B1:7 + 0 coerces the entries to numbers (so that blank cells become 0).
• transpose(B1:1 * 0 + 1) creates a column vector of 1s of suitable size.
• matrix multiplication mmult by a column of 1s amounts to summing each row.
• the wrapper arrayformula indicates that the operations are to be done on arrays.