Maybe this isn't the most elegant way, but it should work. dd$g <- -1 dd$g[dd$aa == "a"] <- 1
Cheers, Thierry ------------------------------------------------------------------------ ---- ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Reseach Institute for Nature and Forest Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, methodology and quality assurance Gaverstraat 4 9500 Geraardsbergen Belgium tel. + 32 54/436 185 [EMAIL PROTECTED] www.inbo.be Do not put your faith in what statistics say until you have carefully considered what they do not say. ~William W. Watt A statistical analysis, properly conducted, is a delicate dissection of uncertainties, a surgery of suppositions. ~M.J.Moroney -----Oorspronkelijk bericht----- Van: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Namens Shubha Vishwanath Karanth Verzonden: maandag 19 februari 2007 14:36 Aan: r-help Onderwerp: [R] categorical column to numeric column Hi R, Let 'dd' be a data frame given as: dd=data.frame(aa=c("a","a","b","a","b","b"),bb=c(1,1,1,2,3,4)) Now I want to create a column 'g' such that if dd$aa=a then dd$g=1 else dd$g= -1 . So, I gave the below syntax: if((dd$aa)=="a") dd$g=1 else dd$g= -1 But I get the error message as: Warning message: the condition has length > 1 and only the first element will be used in: if ((dd$aa) == "a") dd$g = 1 else dd$g = -1 and dd= > dd aa bb g 1 a 1 1 2 a 1 1 3 b 1 1 4 a 2 1 5 b 3 1 6 b 4 1 > Please let me know what is the error I am doing? [[alternative HTML version deleted]] ______________________________________________ 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.
