That's much better. thanks! I was sure I'd looked at that but then for some reason stuck with just if.
Again, as a total a newb I appreciate the help. - Mark On Sun, Jul 19, 2009 at 2:26 PM, Duncan Murdoch<murd...@stats.uwo.ca> wrote: > On 19/07/2009 5:17 PM, Mark Knecht wrote: >> >> 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$f = with(DF, (c*d)*Test + (c+d)*!Test) > > Use ifelse(). > > DF$f <- with(DF, ifelse(a == b, c*d, c+d)) > > Duncan Murdoch > >> >> DF >> >> ______________________________________________ >> 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.
