[R] aggregation with two statistical functions - mean and variance

[Gabor Grothendieck]

On Dec 25, 2007 4:41 AM, Pfeiffer & Koberstein Immobilien GmbH - Ralf
Pfeiffer <ralf.pfeiffer at pfeiffer-koberstein-immobilien.de> wrote:
> thank you,  I downloaded and installed the package. With library(help="doBy")
> I got the information about this package.
>
> But when I use the syntax
>
> summaryBy(daten[,c(3:4)], list(A,B), Fun=c(var,mean))
>
> I got the following error:
> <<Fehler: konnte Funktion "summaryBy" nicht finden>> (error: couldn't find
> function summaryBy)
>
> I tried before
> require(doBy), but this doesn't work neither.
>
> What can I do?

Make sure you did this:

install.packages("doBy")
library(doBy)
library(help = doBy)
?summaryBy
example(summaryBy)

which installs the package on your computer, loads the package into your
session, shows help for the package, shows help
for the summaryBy function and runs the examples, respectively. Read
the help page carefully and follow the examples.

Also read the posting guide and follow the instructions on the
last line of every message to r-help.