Minter! Is there an R cookbook? which lists this kind of common problem and common solution?
On Thu, 16 Sep 2004, Dimitris Rizopoulos wrote: >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
