Dear Gabor and Dimitris, Simple, once you know! It is these little exceptions on the R notation that get me stuck. Now I am on the loose again!
Thanks, Sander. Dimitris Rizopoulos wrote: > you need to use quotes, i.e., > > a[a$y > 0.5, "y"] <- 1 > > you can also use > > a$y[a$y > 0.5] <- 1 > > > I hope it helps. > > Best, > Dimitris > > ---- > Dimitris Rizopoulos > Ph.D. Student > Biostatistical Centre > School of Public Health > Catholic University of Leuven > > Address: Kapucijnenvoer 35, Leuven, Belgium > Tel: +32/(0)16/336899 > Fax: +32/(0)16/337015 > Web: http://med.kuleuven.be/biostat/ > http://www.student.kuleuven.be/~m0390867/dimitris.htm > > > ----- Original Message ----- > From: "Sander Oom" <[EMAIL PROTECTED]> > To: <r-help@stat.math.ethz.ch> > Sent: Friday, August 04, 2006 1:48 PM > Subject: [R] Data frame referencing? > > >> Dear R users, >> >> When you do: >>> x <- rnorm(10) >>> y <- rnorm(10) >>> z <- rnorm(10) >>> a <- data.frame(x,y,z) >>> a$x >> [1] 1.37821893 0.21152756 -0.55453182 -2.10426048 -0.08967880 >> 0.03712110 >> [7] -0.80592149 0.07413450 0.15557671 1.22165341 >> >> Why does this not work: >>> a[a$y>0.5,y] <-1 >> Error in "[<-.data.frame"(`*tmp*`, a$y > 0.5, y, value = 1) : >> only 0's may be mixed with negative subscripts >> >> While this works: >>> a[a$y>0.5,2] <-1 >>> a >> x y z >> 1 1.37821893 -1.0887363 1.7340522 >> 2 0.21152756 -0.7256467 -1.3165373 >> 3 -0.55453182 1.0000000 -2.1116072 >> 4 -2.10426048 -0.4898596 -1.5863823 >> 5 -0.08967880 1.0000000 -0.9139706 >> 6 0.03712110 1.0000000 -1.3004970 >> 7 -0.80592149 -0.7004193 -0.1958059 >> 8 0.07413450 1.0000000 -1.3574303 >> 9 0.15557671 -0.3335407 -2.1991236 >> 10 1.22165341 1.0000000 -0.7576708 >> >> For a complex loop I would prefer to reference the right colomn by >> name, >> not by number! Now, when the colomns change, I need to check my code >> to >> make sure that the right colomns are referenced. >> >> Suggestions much appreciated! >> >> Thanks in advance, >> >> Sander. >> >> ______________________________________________ >> R-help@stat.math.ethz.ch 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. >> > > > Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm > > ______________________________________________ > R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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.