Re: [R] Creating Observation ID

From: Robert Baer <rbaer_at_atsu.edu>
Date: Tue, 10 May 2011 08:07:19 -0500

Thanks Bill and William. Both solutions work, and both have introduced me to whole new R functions which I'm still wrapping my head around.

What a great resource this list is.

Thanks again,
Rob



Robert W. Baer, Ph.D.
Professor of Physiology
Kirksville College of Osteopathic Medicine A. T. Still University of Health Sciences 800 W. Jefferson St.
Kirksville, MO 63501
660-626-2322
FAX 660-626-2965

From: "William Dunlap" <wdunlap_at_tibco.com> Sent: Monday, May 09, 2011 5:17 PM
To: "Robert Baer" <rbaer_at_atsu.edu>; <R-help_at_r-project.org> Subject: RE: [R] Creating Observation ID

> Does the following work for you?
>
> > df2 <- transform(df, ObsID=ave(rep(0,length(Group)), Group,
> FUN=seq_along))
> > head(df2)
> Value Group ObsID
> 1 -0.0025132 B 1
> 2 -1.2456156 A 1
> 3 -2.0531704 B 2
> 4 1.5861770 B 3
> 5 0.1900908 A 2
> 6 0.7197067 B 4
>
> Bill Dunlap
> Spotfire, TIBCO Software
> wdunlap tibco.com
>
>> -----Original Message-----
>> From: r-help-bounces_at_r-project.org
>> [mailto:r-help-bounces_at_r-project.org] On Behalf Of Robert Baer
>> Sent: Monday, May 09, 2011 2:22 PM
>> To: R-help_at_r-project.org
>> Subject: [R] Creating Observation ID
>>
>> If I have a data frame something like:
>> Value=rnorm(30)
>> Group = sample(c('A','B','C'), 30, replace=TRUE)
>> df = data.frame(Value, Group)
>>
>> It seems like it should be simple to create an 'ObsID' column
>> which indicates the observation order of each Value within
>> each of the 3 groups. Somehow, I can't quite see how to do
>> it without manually sub-setting the parent data frame and
>> then putting it back together again.
>>
>> Anyone able to get me started on a cleaner (more R-like) approach?
>>
>> Thanks,
>>
>> Rob
>>
>> ------------------------------------------
>> Robert W. Baer, Ph.D.
>> Professor of Physiology
>> Kirksville College of Osteopathic Medicine
>> A. T. Still University of Health Sciences
>> 800 W. Jefferson St.
>> Kirksville, MO 63501
>> 660-626-2322
>> FAX 660-626-2965
>>
>> [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help_at_r-project.org 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.
>>
>



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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. Received on Tue 10 May 2011 - 13:09:48 GMT

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