Hi Dan, do you need something like that,
dat <- data.frame(V1=rnorm(40000, 10), V2=rnorm(40000, 10)) ratioV1V2 <- ifelse(dat$V1>dat$V2, dat$V1/dat$V2, dat$V2/dat$V1) 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: +32/16/396887 Fax: +32/16/337015 Web: http://www.med.kuleuven.ac.be/biostat/ http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm ----- Original Message ----- From: "Dan Bolser" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, September 16, 2004 2:19 PM Subject: [R] Conditionally swap two columns of a data.frame? > > I am doing this a kinda dumb way, and it is apparetnly taking > forever. > > I have a data frame with two numeric columns. I want to look at their > correlation, and I am looking at the size ratio between the two. > > i.e. > > plot(density(data$V1/data$V2)) > > This kinda gives me a normal curve showing something about the > distribution of the two values. > > I want to make sure that V1/V2 is always > 1 ... > > for (i in 1:length(row.names(data)) ){ > ratioV1V2 <- if(V1>V2) V1/V2 else V2/V1 > } > > This is a bit of a hack, and is taking forever for some reson (about > 40,000 rows in my data.frame). > > I would just like to swap the values in the data frame (to put the bigest > first for example), then use the above plot to get what I want. > > Should I use the DB backend to the data to make the dump in this way? > (involves some hacky sql) > > Considering I am interested in the range of the ratio between V1 and V2, > should I be looking at doing a different analysis? > > I am so dumb, any help is appreciated, > > Dan. > > ______________________________________________ > [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 > ______________________________________________ [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
