Thank you, David, it does work. Could you please explain why? What exactly does changing it to "as matrix" do? Thank you! Dimitri
On Thu, Jul 14, 2011 at 3:25 PM, David Winsemius <dwinsem...@comcast.net> wrote: > > On Jul 14, 2011, at 3:05 PM, Dimitri Liakhovitski wrote: > >> Hello! >> >> I am aggregating using a formula in aggregate - of the type: >> aggregate(cbind(var1,var2,var3)~factor1+factor2,sum,data=mydata) >> >> However, I actually have an object (vector of my variables to be >> aggregated): >> myvars<-c("var1","var2","var3") >> >> I'd like my aggregate formula (its "cbind" part) to be able to use my >> "myvars" object. Is it possible? >> Thanks for your help! >> > > Not sure I have gotten all the way there, but this does work: > > example.agg1<-aggregate(as.matrix(example[myvars])~group+mydate,sum,data=example) > >> example.agg1 > group mydate example[myvars] NA > 1 group1 2008-12-01 4 4.2 > 2 group2 2008-12-01 6 6.2 > 3 group1 2009-01-01 40 40.2 > 4 group2 2009-01-01 60 60.2 > 5 group1 2009-02-01 400 400.2 > 6 group2 2009-02-01 600 600.2 > >> Dimitri >> >> Reproducible example: >> >> mydate = rep(seq(as.Date("2008-12-01"), length = 3, by = "month"),4) >> value1=c(1,10,100,2,20,200,3,30,300,4,40,400) >> value2=c(1.1,10.1,100.1,2.1,20.1,200.1,3.1,30.1,300.1,4.1,40.1,400.1) >> >> example<-data.frame(mydate=mydate,value1=value1,value2=value2) >> >> example$group<-c(rep("group1",3),rep("group2",3),rep("group1",3),rep("group2",3)) >> example$group<-as.factor(example$group) >> (example);str(example) >> >> >> example.agg1<-aggregate(cbind(value1,value2)~group+mydate,sum,data=example) >> # this works >> (example.agg1) >> >> ### Building my object (vector of 2 names - in reality, many more): >> myvars<-c("value1","value2") >> example.agg1<-aggregate(cbind(myvars)~group+mydate,sum,data=example) >> ### does not work >> >> >> -- >> Dimitri Liakhovitski >> Ninah Consulting >> www.ninah.com >> >> ______________________________________________ >> 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. > > David Winsemius, MD > West Hartford, CT > > -- Dimitri Liakhovitski Ninah Consulting www.ninah.com ______________________________________________ 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.