Re: [R] average by group...

From: Doran, Harold <HDoran_at_air.org>
Date: Wed 31 May 2006 - 02:59:43 EST


?tapply  

> -----Original Message-----
> From: r-help-bounces@stat.math.ethz.ch
> [mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of r user
> Sent: Tuesday, May 30, 2006 12:27 PM
> To: rhelp
> Subject: [R] average by group...
>
> I have a dataframe with 700,000 rows and 2 vectors
> (columns): "group" and "score".
>
> I wish to calculate a third vector of length 700000:
> the average score by group. Even though the avarge value
> will repeat, I wish to return the average for that particular
> group for each row.
>
> (I know I can do this by calculating each group's average and
> then using the merge command, but as my calculations get more
> complex and my data set gets larger, the merge command seems
> to be fairly slow.)
>
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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 Received on Wed May 31 03:04:53 2006

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