A Singh wrote: > Dear List, > > I'm having a curious problem with lapply(). I've used it before to > convert a subset of columns in my dataframe, to factors, and its worked. > But now, on re-running the identical code as before it just doesn't > convert the columns into factors at all. > > As far as I can see I've done nothing different, and its strange that it > shouldn't do the action. > > Has anybody come across this before? Any input on this strange issue > much appreciated.. > > Hope I haven't missed something obvious. > > Thanks a lot, > > Aditi > > (P.s.- I've tried converting columns one by one to factors this time, > and that works. > >> P1L55<-factor(P1L55) >> levels(P1L55) >> [1] "0" "1" > > Code: > > prm<-read.table("P:\\..... .csv", header=T, ...sep=",", ...) > > prmdf<-data.frame(prm) > > prmdf[2:13]<-lapply(prmdf[2:13], factor) ## action performed, no error > message > > ##I tried to pick random columns and check > >> levels(P1L55) >> NULL > >> is.factor(P1L96) >> FALSE
Make sure that you are looking in the same object that you changed. E.g. attach(prmdf) prmdf[2:13]<-lapply(prmdf[2:13], factor) levels(P1L55) is not going to work levels(prmdf$P1L55) should, or attaching _after_ the change. Also, make sure that you don't have P1L55 et al. sitting in the global enviromnent. -- O__ ---- Peter Dalgaard Ă˜ster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalga...@biostat.ku.dk) FAX: (+45) 35327907 ______________________________________________ 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.