Re: [R] "Reversal" of Aggregation

From: Achim Zeileis <Achim.Zeileis_at_wu-wien.ac.at>
Date: Mon 29 Jan 2007 - 22:15:42 GMT

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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>
>



R-help@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. Received on Tue Jan 30 09:24:48 2007

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