Gabor Grothendieck <[EMAIL PROTECTED]> writes:
> On 6/26/05, Tudor Bodea <[EMAIL PROTECTED]> wrote:
> > Dear useRs,
> >
> > Is there a way to convert a list generated by "by" command into a data
> > frame?
>
> Here is an example which creates a by object whose elements
> are the first row of each Species of iris. The next line converts
> that to a data frame:
>
> by.object <- by(iris, iris$Species, head, 1)
> do.call("rbind", by.object)
Also, check if aggregate() does the trick:
> aggregate(iris, list(iris$Species), head, 1)
Group.1 Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1 setosa 5.1 3.5 1.4 0.2 1
2 versicolor 7.0 3.2 4.7 1.4 2
3 virginica 6.3 3.3 6.0 2.5 3
> by.object <- by(iris, iris$Species, head, 1)
> do.call("rbind", by.object)
Sepal.Length Sepal.Width Petal.Length Petal.Width Species
setosa 5.1 3.5 1.4 0.2 setosa
versicolor 7.0 3.2 4.7 1.4 versicolor
virginica 6.3 3.3 6.0 2.5 virginica
But notice the differences...
--
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907
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