[R] "Reversal" of Aggregation

[Gabor Grothendieck]

Or equivalently:

  as.data.frame.table(mymatrix)

On 1/29/07, Achim Zeileis <Achim.Zeileis at wu-wien.ac.at> wrote:
>
>
> On Mon, 29 Jan 2007, Roland Rau wrote:
>
> > Dear all,
> >
> > given I have a data.frame in a format like this
> >
> > mydf <- data.frame(age=rep(1:3,5),
> >                    year=c(rep(1996,3), rep(1997,3), rep(1998,3),
> >                      rep(1999,3), rep(2000,3)),
> >                    income=1:15)
> > mydf
> >
> >
> > Now I convert it to some 2D-frequency table like this:
> > mymatrix <- tapply(X=mydf$income, INDEX=list(mydf$age, mydf$year),
> >                    FUN=sum)
> > mymatrix
> >
> >
> > My question is:
> > How can I go the opposite way, i.e. from 'mymatrix' to 'mydf'?
> > Is there an elegant way?
>
> You could do
>  as.data.frame(as.table(mymatrix))
> and then set appropriate column names. (The first two variables are also
> coded as "factor"s which might or might not be what you want in this
> example.)
>
> Z
>
>
> > Thanks,
> > Roland
> >
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
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> > 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.
> >
> >
>
> ______________________________________________
> 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.
>