[R] Aggregating data

[Chuck Cleland]

David Kaplan wrote:
> Chuck and others.  Here is the problem I need help on.  Thanks.
> 
> --------------------
> 
> I want to follow-up on a question I had a week or so ago.  I want to 
> aggregate a very large data set.  Generally in a program such as SPSS, 
> one chooses a so-called "break variable" that is the variable, and then 
> the remaining variables are aggregated by that variable with some 
> summary statistic calculated - such as the mean.
> 
> I played with "aggregate" in R and found that it requires a "by" 
> statement listing the variables.  But I don't see how I can aggregate on 
> one variable and create the summary statistics on the remaining 
> variables.  I hope that was clear.  Thanks for an advice in advance.

  Another example similar to Gabor's and Harold's:

library(nlme) # to get Orthodont data

aggregate(Orthodont[,1:2], by = list(Subject = Orthodont$Subject), FUN =
mean)

> David
> ===========================================================================
> David Kaplan, Ph.D.
> Professor
> Department of Educational Psychology
> University of Wisconsin - Madison
> Educational Sciences, Room, 1061
> 1025 W. Johnson Street
> Madison, WI 53706
> 
> email: dkaplan at education.wisc.edu
> homepage: http://www.education.wisc.edu/edpsych/facstaff/kaplan/kaplan.htm
> Phone: 608-262-0836
> ===========================================================================
> 
> Chuck Cleland wrote:
>> David Kaplan wrote:
>>> The problem is that this doesn't seem to give what I want.  I did look 
>>> at this.  Perhaps doBy will work - haven't tried it yet.  But, any other 
>>> suggestions are much appreciated.
>> David:
>>   Your posts on aggregating came to the list without any text in the
>> body of the message (I believe Petr sent a response based only on the
>> subject).  You might get more specific and helpful suggestions if you
>> send a small example of what you are trying to do and why aggregate()
>> does not work for you.  Also, be sure to send messages in plain text
>> rather than HTML.
>>
>> hope this helps,
>>
>> Chuck Cleland
>>
>>> ===========================================================================
>>> David Kaplan, Ph.D.
>>> Professor
>>> Department of Educational Psychology
>>> University of Wisconsin - Madison
>>> Educational Sciences, Room, 1061
>>> 1025 W. Johnson Street
>>> Madison, WI 53706
>>>
>>> email: dkaplan at education.wisc.edu
>>> homepage: http://www.education.wisc.edu/edpsych/facstaff/kaplan/kaplan.htm
>>> Phone: 608-262-0836
>>> ===========================================================================
>>>
>>> Petr Pikal wrote:
>>>> Similar answer as last time
>>>>
>>>> aggregate, tapply, by or ppackage doBy
>>>>
>>>> HTH
>>>>
>>>> PS. If you want to add some other text then subject in your post do 
>>>> not use HTML posting as recommended in posting guide.
>>>>
>>>> Petr
>>>>
>>>>
>>>> On 28 Nov 2006 at 22:04, David Kaplan wrote:
>>>>
>>>> Date sent:      	Tue, 28 Nov 2006 22:04:09 -0600
>>>> From:           	David Kaplan <dkaplan at education.wisc.edu>
>>>> To:             	r-help at stat.math.ethz.ch
>>>> Subject:        	[R] Aggregating data
>>>>
>>>>> ______________________________________________
>>>>> R-help at stat.math.ethz.ch mailing list
>>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>>> PLEASE do read the posting guide
>>>>> http://www.R-project.org/posting-guide.html and provide commented,
>>>>> minimal, self-contained, reproducible code.
>>>> Petr Pikal
>>>> petr.pikal at precheza.cz
>>>>
>>> ______________________________________________
>>> R-help at stat.math.ethz.ch mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 

-- 
Chuck Cleland, Ph.D.
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