?by FUN: a function to be applied to data frame subsets of 'data'.
...: further arguments to 'FUN'.
by (SS, year, sum)
/E
Emilie Berthiaume wrote:
Hi,
I'm just getting started with R and I'm having problems with some simple operations: I want to get the the sum of the column "SStot" for each year using the function by. The data set is named "SS". I've tried this:
by (SS, year, sum(SStot))
and it's not working. Is it because there's a different number of rows for each year? How else can I do this?
-- Emilie Berthiaume Graduate student Biology Departement Université de Sherbrooke 2500 boul. de l'Université Sherbrooke, Québec J1K 2R1 CANADA
Tél: 1-819-821-8000 poste 2059 Fax: 1-819-821-8049 [EMAIL PROTECTED]
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Dipl. bio-chem. Witold Eryk Wolski MPI-Moleculare Genetic
Ihnestrasse 63-73 14195 Berlin _
tel: 0049-30-83875219 'v'
http://www.molgen.mpg.de/~wolski / \
mail: [EMAIL PROTECTED] ---W-W----
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