ifelse accomplishes this pretty easily (at least I think it does what you want)
Look at ?apply too. HTH, Andy ## Try this foo.dat <- data.frame(Var1 = rnorm(40000, 1, 1), Var2 = (rnorm(40000, 1, 1) * 0.25)) plot(density(foo.dat$Var1 / foo.dat$Var2)) RatioOne <- ifelse(foo.dat$Var1 > foo.dat$Var2, foo.dat$Var1 / foo.dat$Var2, foo.dat$Var2 / foo.dat$Var1) RatioTwo <- numeric() for (i in 1:nrow(foo.dat)) { RatioTwo[i] <- if(foo.dat$Var1[i] > foo.dat$Var2[i]) foo.dat$Var1[i] / foo.dat$Var2[i] else foo.dat$Var2[i] / foo.dat$Var1[i] } cor(RatioOne, RatioTwo) ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html