> -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Mark Knecht > Sent: Sunday, July 19, 2009 2:18 PM > To: r-help > Subject: [R] ifelse choices in a data.frame? > > Hi, > In my data.frame I wanted to essentially write > > If(Test) c*d else c+d > > but that doesn't work. I found I could do it mathematically, but it > seems forced and won't scale well for nested logic. I have two > examples below writing columns e & f, but I don't think the code is > self-documenting as it depends on knowing that Test is a TRUE/FALSE. > > Is there a better way to do the following? > > Thanks, > Mark > > > DF <- data.frame(cbind(a=1:4, b=1:2, c=1:8, d=1:16, e=0, f=0)) > DF$Test <- with(DF, a == b) > > DF$e = (DF$c*DF$d) * DF$Test + (DF$c+DF$d) * !DF$Test > > DF$f = with(DF, (c*d)*Test + (c+d)*!Test) > > DF
Mark, Why can't you use ifelse() ? DF$g <- with(DF, ifelse(Test,c*d,c+d)) Have I missed something in what you are doing? Dan Daniel Nordlund Bothell, WA USA ______________________________________________ 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.
