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

[Pfeiffer & Koberstein Immobilien GmbH - Ralf Pfeiffer]

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?

----- Original Message ----- 
From: "Gabor Grothendieck" <ggrothendieck at gmail.com>
To: "Agrarimmobilien" <ralf.pfeiffer at agrarimmobilien.info>
Cc: <r-help at r-project.org>
Sent: Monday, December 24, 2007 10:48 PM
Subject: Re: [R] aggregation with two statistical functions - mean and 
variance


> See summaryBy in the doBy package.
>
> On Dec 24, 2007 4:27 PM, Agrarimmobilien
> <ralf.pfeiffer at agrarimmobilien.info> wrote:
>> Hello,
>>
>> using the syntax
>>
>> aggregate(daten[,c(3,4)], list(A,B), mean)
>>
>> I'm getting the following data.frame:
>>
>>
>>    A     B        C                    D
>> 1  35    1         6.16000          5
>> 2  47    1        31.24333         20
>> 3  54    1        26.81773         2
>> 4   3     2        12.99000         7
>> 5   4     2         6.49000          1
>>
>> C and D are both means. But now I want to have: C is mean, D is variance.
>>
>> How can I do this by using/ changing the aggregation syntax?
>>
>> Thanks!
>>
>> Macki
>>
>> ______________________________________________
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>> PLEASE do read the posting guide 
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>