[R] how calculate mean for each group
Marc Schwartz
MSchwartz at medanalytics.com
Thu Oct 2 17:41:34 CEST 2003
On Thu, 2003-10-02 at 10:11, Simon Fear wrote:
> A little more succinctly and I hope also helpful:
>
> > with(df, aggregate(list(mean=treatment),
> list(group = group, duplicate = duplicate), mean))
>
> Note that the name of the summary of treatment is likely
> best to be different from the name of the treatment
> variable itself. It is tempting to do something fancy picking
> up the name of the called function automatically, but
> I mostly use an unnamed summary function (x) { ...}, so I won't
> bother.
>
> (BTW did I ever mention here how much I prefer with() to
> attach()/forget.to.detach() ?)
LOL...
I supposed that this might be the time to raise the possibility of an
"Obfuscated R" contest? ;-)
Thanks Simon.
Marc
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