Hi. There have been thoughts of adding .I for that. In the meantime something like this should be faster: DT[DT[,X1==max(X1),by='x,y,z'][[4]]]
> I know that we shouldn't subset .SD, but I would like to return the row > from each group that corresponds to a max value in one of the columns. > Here's how I'm doing it currently: > > maxrows<- df.dt[, .SD[which(X1== max(X1)),], by = list(Var1, Var2, Var3)] > > Is there a better way? > > Thank you kindly, > > Matthew > _______________________________________________ > datatable-help mailing list > [email protected] > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
