If I understood correctly, the initial post asked for a vector of the same
length as the original one. This is why I suggested:

       tapply(Measure,Month,mean)[as.character(Month)]

btw, this is handy way to compute deviations from the means of subgroups (x
- tapply(x, group, mean)[as.character(group)])

Christophe Pallier


On 5/22/07, John Kane <jrkrideau@yahoo.ca> wrote:
>
> aggregate(Measure, list(Month=Month), mean)
>
> --- Benoit Chemineau <benoitchemineau@gmail.com>
> wrote:
>
> > Hello,
> >    I have a basic problem but i can't figure it out
> > with the
> > table underneath. I would like to compute monthly
> > averages.
> >    I would like to have the average measure for
> > month #5 for the first
> > three rows (the same number in the first three
> > lines) and the average
> > measure for month #6 for the last four rows ((the
> > same number in the first
> > three lines) in a separate vesctor (let's call it
> > 'result')
> >    I tried to use a "while" statement inside a "for"
> > loop but it doesn't
> > seem to work.
> >    Can someone please help me with this ?
> >
> >    Measure Month
> >    2.28 5
> >    14.04 5
> >    0.60 5
> >    0.21 6
> >    0.96 6
> >    0.75 6
> >    1.28 6
> >
> >    Thank you !
> >
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@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@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.
>



-- 
Christophe Pallier (http://www.pallier.org)

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