[R] tapply

[Henrique Dallazuanna]

I also don't understand, but perhaps:

with(df, tapply(aps, list(class, id), mean))


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O


On 19/07/07, sigalit mangut-leiba <smangut at gmail.com> wrote:
> hello,
> i want to compute the mean of a variable ("aps") for every class
> (1,2, and 3).
> every id have a few obs., "aps" and class are constant over id.
> like this:
> id   aps     class
> 1      11       2
> 1      11       2
> 1      11       2
> 1      11       2
> 1      11       2
> 2       8        3
> 2       8        3
> 2       8        3
> 3      12       2
> 3      12       2
> .
> .
>
> i tried:
>
> tapply(icu1$aps_st, icu1$hidclass, function(z) mean(unique(z)))
>
> but it's counting every row and not every id.
>
> thank you,
>
> Sigalit.
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
>