arrayformula sum in Google spreadsheet

Question

How do you arrayformula() a sum() such as:

=sum(A1:H1)

I need to go down 1000 rows.

Answer 1

Let us not complicate this. Simply put parenthesis in each of the array in the range.

=arrayformula( Sum( (A1:A):(H1:H) )

This spans not only upto 1000 rows but upto infiinity.

If you really want to limit then go

=arrayformula( Sum( (A1:A1000):(H1:H1000) )