[R] Help in getting aggregated data

[Deepak Manohar]

Both aggregate and custom functionality given by Jim works.
Thanks

On 4/1/07, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
> Try this:
>
> aggregate(a[3], a[1:2], max)
>
>
> On 3/31/07, Deepak Manohar <deepakmanohar at gmail.com> wrote:
> > Hi team,
> >   I have the data of the form:
> >
> > > a<- data.frame(x=c(1,2,1,4,3), y=c(1,2,1,4,3), z=c(1,2,3,4,5))
> >
> > I need the output of the form
> >
> > > b<- data.frame(x=c(1,2,3,4), y=c(1,2,3,4), z=(3,2,5,4) )
> >
> > As you can see, the Z value contains the maximum for each of the (x,y)
> > combinations.
> >
> > I used
> > > c<-by(a$z, list(x=a$x, y=a$y), max)
> > > c[,]
> >   y
> > x    1  2  3  4
> >  1  3 NA NA NA
> >  2 NA  2 NA NA
> >  3 NA NA  5 NA
> >  4 NA NA NA  4
> >
> > Not sure If I have any standard function to convert this to the data
> > frame that I need. Can you help me convert the last array into the
> > data frame? If there is any other way apart from using the "by"
> > function, please inform me regarding that as well.
> >
> > -- Deepak Manohar T
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch 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.
> >
>


-- 
Deepak Manohar T
Trilogy
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