Hi, On Tue, May 10, 2011 at 7:56 AM, Nicolas Servant <[email protected]> wrote: > Dear Datatable users, > > I'm interested in using the data.table package to reduce and group high > dimensional data (from next generation sequencing) > I have my data.table which show me for each reads (features), the > associated annotation. > And because one feature can have several annotations, I would like to > group these annotations per feature > The numerical operations on the annotation work well (for instance > length()), but the functions on string values seem to not work (for > instance paste()) > At the end, I would like to have something like : > > reads annot > [1,] 1279_1000_530_F3-ad Simple_repeat, LINE > [2,] 1279_1000_940_F3-ad snRNA > ... > Do you have any suggestion to do that ? > >>dt[1:20,] > > reads annot > [1,] 1279_1000_530_F3-ad Simple_repeat > [2,] 1279_1000_530_F3-ad LINE > [3,] 1279_1000_940_F3-ad snRNA > [4,] 1279_1000_940_F3-ad snRNA > [5,] 1279_1018_1051_F3-ad Simple_repeat
A similar question using paste came up a few days ago ... this should do the trick: R> key(dt) <- 'reads' R> dt[, paste(annot, collapse=','), by=reads] Hope that helps, -steve -- 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
