Dear Cameron, This is not with unique, but it gets the job done. Just create a new variable that is the three variables concatenated together. Then, you can just sum by this variable, like the following:
mymat <- matrix(letters, ncol=3, nrow=260) mymat <- as.data.frame(mymat) mymat$dat <- rnorm(260) mymat$id <- paste(mymat[,1], mymat[,2], mymat[,3]) aggregate(mymat$dat, list(mymat$id), sum) HTH, Dave. On 5/10/06, Robert Citek <[EMAIL PROTECTED]> wrote: > > On May 10, 2006, at 4:02 PM, Guenther, Cameron wrote: > > How can I use unique to extract the rows that have repeated tripid's > > only, not a unique value for each variable but only for TRIPID. I > > then > > want to condense the unique values by summing the CONVUNIT for each > > unique value of TRIPID. > > Thanks, Cameron, for this question. This type of manipulation would > be relatively simple to do in a RDBMS (e.g. MySQL, PostgreSQL, > Oracle, etc.) But I'm curious to see how one would do the same in > R. So, if folks send you solutions off-list, please do post them > back to the list. > > Regards, > - Robert > http://www.cwelug.org/downloads > Help others get OpenSource software. Distribute FLOSS > for Windows, Linux, *BSD, and MacOS X with BitTorrent > > ______________________________________________ > [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 > -- Dave Armstrong University of Maryland Dept of Government and Politics 3140 Tydings Hall College Park, MD 20742 Office: 2103L Cole Field House Phone: 301-405-9735 e-mail: [EMAIL PROTECTED] web: www.davearmstrong-ps.com Facts are meaningless. You can use facts to prove anything that's even remotely true. - Homer Simpson To this day, philosophers suffer from Plato's disease: the assumption that reality fundamentally consists of abstract essences best described by words or geometry. (In truth, reality is largely a probabilistic affair best described by statistics) - Steve Sailer "The Unexpected Uselessness of Philosophy" [[alternative HTML version deleted]] ______________________________________________ [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
