[R] transposing a matrix - row by row?

[Dimitri Liakhovitski]

Thank you very much, Thierry!
Really amazing, the magic melt from reshape. And, in fact, a bit
dangerous - it just do what I need without any efforts on my part!
Dimitri

On Thu, Apr 23, 2009 at 10:40 AM, ONKELINX, Thierry
<Thierry.ONKELINX at inbo.be> wrote:
> Dear Dimitri,
>
> Have a look at melt() from the reshape package.
>
> X<-matrix(c(10,20,30,40,50,60),2,3)
> dimnames(X)<-list(c("1","2"),c("1","2","3"))
> library(reshape)
> melt(X)
>
> HTH,
>
> Thierry
>
>
> ------------------------------------------------------------------------
> ----
> ir. Thierry Onkelinx
> Instituut voor natuur- en bosonderzoek / Research Institute for Nature
> and Forest
> Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,
> methodology and quality assurance
> Gaverstraat 4
> 9500 Geraardsbergen
> Belgium
> tel. + 32 54/436 185
> Thierry.Onkelinx at inbo.be
> www.inbo.be
>
> To call in the statistician after the experiment is done may be no more
> than asking him to perform a post-mortem examination: he may be able to
> say what the experiment died of.
> ~ Sir Ronald Aylmer Fisher
>
> The plural of anecdote is not data.
> ~ Roger Brinner
>
> The combination of some data and an aching desire for an answer does not
> ensure that a reasonable answer can be extracted from a given body of
> data.
> ~ John Tukey
>
> -----Oorspronkelijk bericht-----
> Van: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> Namens Dimitri Liakhovitski
> Verzonden: donderdag 23 april 2009 16:31
> Aan: R-Help List
> Onderwerp: [R] transposing a matrix - row by row?
>
> Hello,
> I have a matrix that is a product of tapply on a larger data set.
> Let's assume it looks like this:
>
> X<-matrix(c(10,20,30,40,50,60),2,3)
> dimnames(X)<-list(c("1","2"),c("1","2","3"))
> (X)
>
>   1   2   3
> 1 10 30 50
> 2 20 40 60
>
> Is there an efficient way of transforming this matrix into the following
> matrix:
>
> rows columns entries
> 1          1          10
> 1          2          30
> 1          3          50
> 2          1          20
> 2          2          40
> 2          3          60
>
>
> Thank you very much!
> --
> Dimitri Liakhovitski
> MarketTools, Inc.
> Dimitri.Liakhovitski at markettools.com
>
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-- 
Dimitri Liakhovitski
MarketTools, Inc.
Dimitri.Liakhovitski at markettools.com