Re: [R] operation on a data.frame

From: Philipp Pagel <>
Date: Mon, 26 May 2008 12:23:34 +0200

> I would like to obtain a data.frame or matrix in which rows with an
> equal string on column "C1" are averaged. In the previous example, rows
> "One", "Four" and "Five" should be averaged because the three have "A"
> con C1. The resulting row should be: "A" 10/3 28/3 46/3

I think this is waht you are looking for:

aggregate(df[-1], by=list(C1=df$C1), mean)



Dr. Philipp Pagel
Lehrstuhl für Genomorientierte Bioinformatik
Technische Universität München
Wissenschaftszentrum Weihenstephan
85350 Freising, Germany
Institut für Bioinformatik und Systembiologie / MIPS
Helmholtz Zentrum München -
Deutsches Forschungszentrum für Gesundheit und Umwelt
Ingolstädter Landstrasse 1
85764 Neuherberg, Germany

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Received on Mon 26 May 2008 - 10:27:40 GMT

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