Thanks, yes. j and by descriptions now improved in ?data.table. On Tue, 2012-01-10 at 17:35 -0500, Joseph Voelkel wrote: > In ?data.table > > > > “j is evaluated within the frame of the data.table (i.e. it sees > column names as if they are variables). The result is returned. list() > may be omitted when there is just one expression, for convenience.” > > > > I think these used to be identical (?), but now one returns a vector > and the other a data.table. > > > _______________________________________________ > datatable-help mailing list > [email protected] > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
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