Hi Rainer,
thank you for your response.
The combination of melt/cast was what I was looking for.
Now, also the reshape-package and its advantage is a lot clearer
to me.
cheers,
johannes
-------- Original-Nachricht --------
> Datum: Tue, 24 Jan 2012 19:28:43 +0100
> Von: Rainer Schuermann <rainer.schuerm...@gmx.net>
> An: Johannes Radinger <jradin...@gmx.at>
> CC: "r-help@r-project.org" <r-help@r-project.org>
> Betreff: Re: [R] reshape dataframe to array (pivot table)
> Hi,
>
> I wouldn't know how to fill the data into the array form you want, but
> you can get the aggregated data with
>
> dfm <- melt( df )
> dfc <- cast( dfm, LOC ~ variable, sum )
> > dfc
> LOC SPEC1 SPEC2
> 1 1 23 5
> 2 2 23 2
> 3 3 0 0
>
> Hope this helps as a first step!
>
> Rgds,
> Rainer
>
>
> On 2012-01-24 17:15, Johannes Radinger wrote:
> > Hello,
> >
> > I would like to reshape a dataframe into an array. This is kind a
> similar task as Excel performs with a Pivot table. To illustrate it:
> >
> > LOC<- factor(c(1,2,2,3,1,1))
> > SPEC1<- c(0,0,23,0,12,11)
> > SPEC2<- c(1,2,0,0,0,4)
> >
> > df<- data.frame(LOC,SPEC1,SPEC2) # original dataframe
> >
> > a<-
> array(NA,dim=c(length(levels(LOC)),1,2),dimnames=list(levels(LOC),"LOC",c("SPEC1","SPEC2")))
> #new array set up, how it should look like
> >
> > The final array is splitted by the SPEC (for each SPEC an new layer),
> and
> > the LOC is collapsed so that there is only one line per level of LOC.
> > The array should get populated with:
> > 1) the sums
> > 2) and presence/absence (can be easily calculated from sums)
> >
> > What is the best way to do that? I looked into reshape and
> apply...probably one of them is suitable but I don't know how...Or has that
> to be done
> with a loop?
> >
> > cheers,
> > /johannes
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