hi:
I have a datatable with two columns (see below) and I want to create
another column that adds the values of the rows in the first two
columns. I am trying this:
DT[ , col3 :=rowSums(.SD, na.rm = TRUE), .SDcols = c("col1","col2")]
but I get this error:
Error in inherits(x, "data.frame") : object '.SD' not found
do you know why is this? or is there another way to sum by row in a
given number of columns?
Cheers,
Camilo
# col1 col2 col3
#1: NA 0.003745 0.003745
#2: 0.000000 0.007463 0.007463
#3: -0.015038 -0.007407 -0.022445
#4: 0.003817 -0.003731 0.000086
#5: -0.011407 -0.007491 -0.018898