One clue is the help file for "$"... ?" $"
In particular there see the discussion of character indices and the "exact" argument. You can also find this discussed in the Introduction to R document that comes with the software. --------------------------------------------------------------------------- Jeff Newmiller The ..... ..... Go Live... DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... Live: OO#.. Dead: OO#.. Playing Research Engineer (Solar/Batteries O.O#. #.O#. with /Software/Embedded Controllers) .OO#. .OO#. rocks...1k --------------------------------------------------------------------------- Sent from my phone. Please excuse my brevity. On August 29, 2014 1:53:47 AM PDT, Angel Rodriguez <angel.rodrig...@matiainstituto.net> wrote: > >Dear subscribers, > >I've found that if there is a variable in the dataframe with a name >very similar to a new variable, R does not give the correct values to >this latter variable based on the values of a third value: > > >> M <- structure(list(V1 = c(67, 62, 74, 61, 60, 55, 60, 59, >58)),.Names = c("age"), row.names = c(NA, -9L), >+ class = "data.frame") >> M$sample[M$age >= 65] <- 1 >> M > age sample >1 67 1 >2 62 NA >3 74 1 >4 61 NA >5 60 NA >6 55 NA >7 60 NA >8 59 NA >9 58 NA >> N <- structure(list(V1 = c(67, 62, 74, 61, 60, 55, 60, 59, 58), V2 = >c(NA, 1, 1, 1, 1,1,1,1,NA)), >+ .Names = c("age","samplem"), row.names = c(NA, >-9L), class = "data.frame") >> N$sample[N$age >= 65] <- 1 >> N > age samplem sample >1 67 NA 1 >2 62 1 1 >3 74 1 1 >4 61 1 1 >5 60 1 1 >6 55 1 1 >7 60 1 1 >8 59 1 1 >9 58 NA NA > > > >Any clue for this behavior? > > > >My specifications: > >R version 3.1.1 (2014-07-10) >Platform: x86_64-w64-mingw32/x64 (64-bit) > >locale: >[1] LC_COLLATE=Spanish_Spain.1252 LC_CTYPE=Spanish_Spain.1252 >LC_MONETARY=Spanish_Spain.1252 >[4] LC_NUMERIC=C LC_TIME=Spanish_Spain.1252 > >attached base packages: >[1] stats graphics grDevices utils datasets methods base > > >other attached packages: >[1] foreign_0.8-61 > >loaded via a namespace (and not attached): >[1] tools_3.1.1 > > > > >Thank you very much. > >Angel Rodriguez-Laso >Research project manager >Matia Instituto Gerontologico > > > [[alternative HTML version deleted]] > >______________________________________________ >R-help@r-project.org mailing list >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide >http://www.R-project.org/posting-guide.html >and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.