[R] Sorting data from one column with strings

Ramsvatn Silje
Thu, 04 Nov 2010 12:28:06 -0000

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 Troms?
Norway