row-by-row operations and updates in data.table

Question

I ended up with a big data.table and I have to do operations per row. (yes... I know that this is clearly not what data.table are for)

R) set.seed(1)
R) DT=d         


        

Answer 1

This spells out the steps in case you want to use a different function:

cols    <- names(DT)[grepl('^V[[:digit:]]+$',names(DT))]
newcols <- c("min","max")
myfun   <- range
DT[,(newcols):=as.list(myfun(.SD)),.SDcols=cols,by=1:nrow(DT)]