How do I achieve the following partitioning effect: dt = data.table (x=10:14, y=20:24) aggregate (dt, by = list (dt$x %% 3), FUN = list)
Group.1 x y 1 0 12 22 2 1 10, 13 20, 23 3 2 11, 14 21, 24 If I try the following it doesn't work (and I think I know why): dt [, by = x %% 3, j = list(y)] x y 1: 1 20 2: 1 23 3: 2 21 4: 2 24 5: 0 22 (while with j = max (y) it of course works, generating a "V1" column) Also, how do I name the result of the j-expression (by default the resulting column is "V1")? _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
