Try this also:

xtabs(values ~ diagnosis + marker, data=dataframe)

On Wed, Nov 12, 2008 at 2:31 PM, Thorsten Raff <t.raff@med2.uni-kiel.de>wrote:

> Hello
>
> I have the problem that I want to transform a dataframe as generated by
>
> diagnosis <- rep(diagnosis[1:3], 3)
> marker <- gl(3,3)
> values <- rnorm(9)
> dataframe <- cbind(diagnosis, marker, values)
> dataframe <- dataframe[c(1:5, 7:9), ]
>
> into a matrix where levels(diagnosis) is indicating the rows of the matrix,
> levels(marker) the columns and values are the actual content of the matrix.
> However, as can been seen in the dataframe, some observations are missing
> and
> should result in <NAs> in the resulting matrix, giving a result like this:
>
> marker              1         2         3
> diagnosis1      value   value   value
> diagnosis2      value   value   value
> diagnosis3      value      NA    value
>
> Can anyone help out with some code for this? I have tried to look this up
> in
> the mailing list as it has probably been answered before but only found
> aspects of the problem which I was just not able to plumb together.
>
> Many thanks in advance, I hope this is not to much of an insult for the
> list.
>
> Thorsten
>
> P.S: I have already sent this message to the mailing list, howver I got a
> bounce-message back, so hopefully this is no duplicate entry. Sorry for any
> inconvenience that this may confer.
>
>
> --
> Thorsten Raff
> 2nd Medical Department,
> University Hospital Schleswig-Holstein, Campus Kiel
> Chemnitzstraße 33
> 24116 Kiel
> GERMANY
>
> phone: +49 431 1697-5234
> fax:   +49 431 1697-1264
>
> email: t.raff<at>med2.uni-kiel.de
> web:   www.uk-s-h.de
>
>
>
>
> ______________________________________________
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

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