Re: [R] data transformation

From: Christos Hatzis <christos.hatzis_at_nuverabio.com>
Date: Fri, 02 May 2008 18:29:57 -0400

Christian,

You need to use reshape to convert to the 'long' format. Check the help page ?reshape for details.

>dat <- read.table('clipboard', header=TRUE)
>dat

   site lat lon spec1 spec2 spec3 spec4

1 site1  10  11     1     0     1     0
2 site2  20  21     1     1     1     0
3 site3  30  31     0     1     1     1

> dat.long <- reshape(dat, varying = list(names(dat)[4:7]),
timevar="species",

        times=names(dat)[4:7], direction="long")
> dat.long

         site lat lon species spec1 id
1.spec1 site1  10  11   spec1     1  1
2.spec1 site2  20  21   spec1     1  2
3.spec1 site3  30  31   spec1     0  3
1.spec2 site1  10  11   spec2     0  1
2.spec2 site2  20  21   spec2     1  2
3.spec2 site3  30  31   spec2     1  3
1.spec3 site1  10  11   spec3     1  1
2.spec3 site2  20  21   spec3     1  2
3.spec3 site3  30  31   spec3     1  3
1.spec4 site1  10  11   spec4     0  1
2.spec4 site2  20  21   spec4     0  2
3.spec4 site3  30  31   spec4     1  3

> dat.long[dat.long$spec1 == 1, ]
site lat lon species spec1 id 1.spec1 site1 10 11 spec1 1 1 2.spec1 site2 20 21 spec1 1 2 2.spec2 site2 20 21 spec2 1 2 3.spec2 site3 30 31 spec2 1 3 1.spec3 site1 10 11 spec3 1 1 2.spec3 site2 20 21 spec3 1 2 3.spec3 site3 30 31 spec3 1 3 3.spec4 site3 30 31 spec4 1 3

-Christos

> -----Original Message-----
> From: r-help-bounces_at_r-project.org
> [mailto:r-help-bounces_at_r-project.org] On Behalf Of Christian Hof
> Sent: Friday, May 02, 2008 5:28 PM
> To: r-help_at_r-project.org
> Subject: [R] data transformation
>
> Dear all,
> how can I, with R, transform a presence-absence (0/1) matrix
> of species occurrences into a presence-only table (3 columns)
> with the names of the species (1st column), the lat
> information of the sites (2nd column) and the lon information
> of the sites (3rd column), as given in the below example?
> Thanks a lot for your help!
> Christian
>
>
> my dataframe:
>
> site lat lon spec1 spec2 spec3 spec4
> site1 10 11 1 0 1 0
> site2 20 21 1 1 1 0
> site3 30 31 0 1 1 1
>
>
> my desired new dataframe:
>
> species lat lon
> spec1 10 11
> spec1 20 21
> spec2 20 21
> spec2 30 31
> spec3 10 11
> spec3 20 21
> spec3 30 31
> spec4 30 31
>
>
>
> --
> Christian Hof, PhD student
>
> Center for Macroecology & Evolution
> University of Copenhagen
> www.macroecology.ku.dk
> &
> Biodiversity & Global Change Lab
> Museo Nacional de Ciencias Naturales, Madrid www.biochange-lab.eu
>
> mobile ES .. +34 697 508 519
> mobile DE .. +49 176 205 189 27
> mail .. chof_at_bio.ku.dk
> mail2 .. vogelwart_at_gmx.de
> blog .. www.vogelwart.de
>
> ______________________________________________
> R-help_at_r-project.org 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.
>
>



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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. Received on Fri 02 May 2008 - 22:28:54 GMT

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