As you can see there are lots of ways to get this done! But in vanilla R: test = data.frame(A=rep(1,6),B=c(1,1,1,2,2,3),C=1:6) with(test,aggregate(C,list(A,B),length)) does what you've asked, I think. On Tue, Apr 3, 2012 at 1:26 PM, Steven Raemaekers <s.raemaek...@sig.eu>wrote:
> Hi, > > I have a query which I would like to translate into R, but I do not know > how to do it in an easy way. > Assume a data frame has columns A, B and C: > > A B C > 1 1 3 > 1 1 4 > 1 1 5 > 1 2 6 > 1 2 7 > 1 3 8 > > The query is as follows: > > select A, B, count(*) > from data.frame > group by A, B > order by count(*) desc > > How do I translate this into R statements in such way that the result is a > data frame structured as follows: > > A B count(*) > 1 1 3 > 1 2 2 > 1 3 1 > > Thanks, > > Steven > ______________________________________________ > 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. > -- Drew Tyre School of Natural Resources University of Nebraska-Lincoln 416 Hardin Hall, East Campus 3310 Holdrege Street Lincoln, NE 68583-0974 phone: +1 402 472 4054 fax: +1 402 472 2946 email: aty...@unl.edu http://snr.unl.edu/tyre http://aminpractice.blogspot.com http://www.flickr.com/photos/atiretoo [[alternative HTML version deleted]] ______________________________________________ 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.
