on 02/07/2009 01:47 PM Drew Garey wrote:
> Hello all,
>
>
>
> I have a *.csv file that looks like this (actual file is orders of magnitude
> larger):
>
>
>
> Site taxa no.ind
>
> forest LMA 1
>
> forest LCY 1
>
> forest SCO 1
>
> meadow LMA 2
>
> meadow LCY 1
>
> meadow PNT 3
>
>
>
> I am interested in, but have failed to create, code that efficiently
> converts it to a site-by-taxa matrix or data frame that looks like this:
>
>
>
> LMA LCY SCO PNT
>
> Forest 1 1 1 0
>
> Meadow 2 1 0 3
>
>
>
>
>
> With no repeating taxa names and zeros where a taxon is not listed for a
> site. Any help would be greatly appreciated.
See ?xtabs
If your data is in a data frame called 'DF':
> DF
Site taxa no.ind
1 forest LMA 1
2 forest LCY 1
3 forest SCO 1
4 meadow LMA 2
5 meadow LCY 1
6 meadow PNT 3
> xtabs(no.ind ~ Site + taxa, data = DF)
taxa
Site LCY LMA PNT SCO
forest 1 1 0 1
meadow 1 2 3 0
HTH,
Marc Schwartz
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