Hi, I see what the problem is -- we need to provide a droplevels.data.table S3 method, because the way the droplevels.data.frame method works isn't compatible with data.table indexing.
Will fix: https://r-forge.r-project.org/tracker/index.php?func=detail&aid=1841&group_id=240&atid=975 Thanks for raising the flag. Cheers, -steve On Tue, Feb 21, 2012 at 12:38 PM, pchalasani <[email protected]> wrote: > Surprising that this wasn't noticed before, or perhaps I'm not following > some recommended idiom to drop levels when using data.table. The following > code illustrates the bug clearly: The bug remains regardless of whether I > use "subset" or simply use dt1 = dt[ name != 'a' ]. > > > > d <- data.table(name = c('a','b','c'), value = 1:3) > dt <- data.table(d) > setkey(dt,'name') > dt1 <- subset(dt,name != 'a') # or dt1 <- dt[ name != 'a' ] > > dt1 > name value > [1,] b 2 > [2,] c 3 > > > droplevels(dt1) > name value > [1,] b 1 > [2,] c 3 > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/BUG-droplevels-mangles-subsetted-data-table-tp4407694p4407694.html > Sent from the datatable-help mailing list archive at Nabble.com. > _______________________________________________ > datatable-help mailing list > [email protected] > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help -- Steve Lianoglou Graduate Student: Computational Systems Biology | Memorial Sloan-Kettering Cancer Center | Weill Medical College of Cornell University Contact Info: http://cbio.mskcc.org/~lianos/contact _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
