Thanks Matthew! DT[X, val:=val.1] now works good with 1.8.1. Regards, Cedric
-----Message d'origine----- De : Matthew Dowle [mailto:[email protected]] Envoyé : lundi 18 juin 2012 13:12 À : DUPREZ Cédric Cc : [email protected] Objet : Re: [datatable-help] Join and replacement Hi, You'll need 1.8.1 for that : install.packages("data.table", repos="http://R-Forge.R-project.org";) Also check live NEWS link at the top of ?data.table, as there's quite a lot in this version. Also this recent question is related : http://stackoverflow.com/questions/11030614/how-to-best-join-one-column-of-a-data-table-with-another-column-of-the-same-data Matthew > Dear all, > > I'm trying to replace values within a data.table object with values > comming from another data.table object, joining them together. > > Here is an example: > DT <- data.table("id"=c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, > 16) > , val=c(0, 0, 1, 1, 2, 2, 0, 0, 1, 1, 2, 2, 2, 0, 1, 0) > , key = "id") > DT2 <- data.table("id"=c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, > 15, 16) > , val=c(3, 3, 3, 5, 5, 5, 5, 3, 6, 4, 3, 2, 3, 5, 4, 4) > , key = "id") > I would like to replace all val = 0 in DT with the corresponding DT2 > values, joining DT and DT2 on "id". > That is, get the following DT : > id val > [1,] 1 3 > [2,] 2 3 > [3,] 3 1 > [4,] 4 1 > [5,] 5 2 > [6,] 6 2 > [7,] 7 5 > [8,] 8 3 > [9,] 9 1 > [10,] 10 1 > [11,] 11 2 > [12,] 12 2 > [13,] 13 2 > [14,] 14 5 > [15,] 15 1 > [16,] 16 4 > > I tried > X <- DT[DT2][val==0,] > DT[X, val:=val.1] > Or DT[X, val:=val.1, roll = T] > > But I always get the following error message: "combining bywithoutby with > := in j is not yet implemented." > > The following code seems to work: > DT[X]$val <- DT[X]$val.1 > But I get a warning message: "In `[<-.data.table`(`*tmp*`, X, value = > list(id = c(1L, 2L, 7L, : > Supplied 2 columns to be assigned a list (length 4) of values (2 > unused)" > > Any suggestion to help me? > > Thanks a lot for your help, > > Cedric > _______________________________________________ > 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
