[Rd] value returned by by()

Seb spluque at gmail.com
Tue Sep 14 20:50:43 CEST 2010

On Tue, 14 Sep 2010 12:02:04 +0200,
Uwe Ligges <ligges at statistik.tu-dortmund.de> wrote:

> It returns a list with athe class attribut set to "by", just use: x <-
> by(.....)  unclass(x)

Thanks Uwe, however, that still returns an array when using the
data.frame method for by():

R> class(unclass(with(warpbreaks, by(warpbreaks[, 1:2], tension, summary))))
[1] "array"

It seems as if the only way to really ensure a list:

R> class(lapply(unclass(with(warpbreaks, by(warpbreaks[, 1:2], tension, summary))), function(x) x))
[1] "list"

but it seems like a waste to call another function just to do this.


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