> x <- read.table(textConnection(" V1 V2 + 1 a 3 + 2 a 2 + 3 b 9 + 4 c 4 + 5 a 7 + 6 b 11"), header=TRUE) > closeAllConnections() > # close; matrix with rownames - easy enough to change into a dataframe if you > want > cbind(tapply(x$V2, x$V1, min)) [,1] a 2 b 9 c 4 >
On Mon, Feb 8, 2010 at 11:39 AM, Jonathan <jonsle...@gmail.com> wrote: > Hi all, > I'm feeling a little guilty to ask this question, since I've > written a solution using a rather clunky for loop that gets the job > done. But I'm convinced there must be a faster (and probably more > elegant) way to accomplish what I'm looking to do (perhaps using the > "merge" function?). I figured somebody out there might've already > figured this out: > > I have a dataframe with two columns (let's call them V1 and V2). All > rows are unique, although column V1 has several redundant entries. > > Ex: > > V1 V2 > 1 a 3 > 2 a 2 > 3 b 9 > 4 c 4 > 5 a 7 > 6 b 11 > > > What I'd like is to return a dataframe cut down to have only unique > entires in V1. V2 should contain a vector, for each V1, that is the > minimum of all the possible choices from the set of redundant V1's. > > Example output: > > V1 V2 > 1 a 2 > 2 b 9 > 3 c 4 > > > If somebody could (relatively easily) figure out how to get closer to > a solution, I'd appreciate hearing how. Also, I'd be interested to > hear how you came upon the answer (so I can get better at searching > the R resources myself). > > Regards, > Jonathan > > ______________________________________________ > 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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ 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.