[R] Aggregating data

[David Kaplan]

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.

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.
>>
>