Hi, There,
I would like to subtotal the number in a specified column for all rows having
the same data for specified columns. The following is the simple example:
> x=matrix(c(1,2,2,0.3,2,2,2,0.5,1,2,1,0.2),3,4,byrow=T)
> rownames(x)=c("R1","R2","R3")
> colnames(x)=c("C1","C2","C3","F")
> x
C1 C2 C3 F
R1 1 2 2 0.3
R2 2 2 2 0.5
R3 1 2 1 0.2
I would like to get the subtotal in column "F" based on same row data in column
"C1" and "C2". The result should be like
C1 C2 SumF
1 2 0.5 # This is 0.3 + 0.2 from R1 and R3
2 2 0.5
Is there a simple way to do this? Any help will be greatly appreciated.
Qiaoping Yuan
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