[R] Sorting data from one column with strings

[jim holtman]

try sqldf:

> x
  Sample_no Species Nitrogen Carbon
1         1     Cod     15.2  -19.0
2         2 Haddock     14.8  -20.2
3         3     Cod     15.6  -18.5
4         4     Cod     13.2  -20.1
5         5 Haddock     14.3  -18.8
> require(sqldf)
> sqldf("select Species, avg(Nitrogen) Nitrogen, avg(Carbon) Carbon from x group by Species")
  Species Nitrogen Carbon
1     Cod 14.66667  -19.2
2 Haddock 14.55000  -19.5


On Thu, Nov 4, 2010 at 8:28 AM, Ramsvatn Silje <silje.ramsvatn at uit.no> wrote:
>
> Hello,
>
> I have tried to find this out some other way, but unsuccessful I have to
> try this list.
> I assume this should be quite simple.
>
> I have a dataset with 4 columns, "Sample_no", "Species", "Nitrogen",
> "Carbon" in csv format. In the species column I have many different
> species with varying number of obs per species
>
> Eg
>
> "Sample_no"     "Species"       "Nitrogen"      "Carbon"
> 1               Cod             15.2            -19.0
> 2               Haddock 14.8            -20.2
> 3               Cod             15.6            -18.5
> 4               Cod             13.2            -20.1
> 5               Haddock 14.3            -18.8
> Etc..
>
> And I want to calculate, mean, standard dev etc per species for the
> observations "Nitrogen" and "Carbon". And later do plots and stats with
> the different species. I will in the end have many species, so need it to
> be "automatic" I can't enter code for every species separate.
>
> Can anyone help me with this? Or if this is the wrong list to sendt this
> question to, where do I send it?
>
> Thank you very much in advance.
>
>
> Best regards
>
> Silje Ramsvatn
>
> PhD-candidate
> University of Tromsø
> Norway
>
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

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