How to get rowSums for selected columns in R

Question

I am a newbie to R and seek help to calculate sums of selected column for each row. My simple data frame is as below.

data = data.frame(location = c(\"a\",\"b\"         


        

Answer 1

Here is a quite simple solution using apply.

output <- data.frame( x1 = apply(data[2:4], 1, sum) ,
                      x2 = apply(data[5:7], 1, sum) )

result:

output
>    x1 x2
> 1  14 13
> 2  66 18
> 3   8 12
> 4 100 24