Using Office365 Excel array formulas, how to calculate ytd totals for all rows and months?

Question

Can one array formula calculate ytd totals for each month and name? See desired results. I tried doing it by row but getting a #calc! error.

Formula:

=LET(data,B5:D7,BYROW(data,LAMBDA(r,SCAN(0,r,LAMBDA(a,v,a+v)))))

Data:

	Jan	Feb	Mar
A	1	2	3
B	4	5	6
C	7	8	9

Answer 1

Another cleaner approach could be using MAKEARRAY(). Give a try to the following formula.

=MAKEARRAY(ROWS(B2:D4),COLUMNS(B2:D4),
LAMBDA(r,c,SUM(TAKE(CHOOSEROWS(B2:D4,r),1,c))))

Answer 2

You getting #CALC! because BYROW() can't return array output. It can only return single value. Try-

=DROP(REDUCE("",BYROW(B2:D4,LAMBDA(rw,TEXTJOIN("|",1,SCAN(0,rw,LAMBDA(a,x,a+x))))),LAMBDA(acc,dt,VSTACK(acc,TEXTSPLIT(dt,"|")))),1)