[Rd] split() - unexpected sorting of results

Peter Meissner retep.meissner at gmail.com
Fri Oct 20 21:53:02 CEST 2017


Thanks, for the explanation.

Still, I think this is surprising bahaviour which might be handled better.

Best, Peter

Am 20.10.2017 9:49 nachm. schrieb "Iñaki Úcar" <i.ucar86 at gmail.com>:

> Hi Peter,
>
> 2017-10-20 21:33 GMT+02:00 Peter Meissner <retep.meissner at gmail.com>:
> > Hey,
> >
> > I found this - for me - quite surprising and puzzling behaviour of
> split().
> >
> >
> > split(1:11, as.character(1:11))
> > split(1:11, 1:11)
> >
> >
> > When splitting by numerics everything works as expected - sorting of
> input
> > == sorting of output -- but when using a character vector everything gets
> > re-sorted alphabetical.
> >
> >
> > Although, there are some references in the help files to what happens
> when
> > using split, I did not find any note on this - for me - rather unexpected
> > behaviour.
>
> As the documentation states,
>
>        f: a ‘factor’ in the sense that ‘as.factor(f)’ defines the
>           grouping, or a list of such factors in which case their
>           interaction is used for the grouping.
>
> And, in fact,
>
> > as.factor(1:11)
>  [1] 1  2  3  4  5  6  7  8  9  10 11
> Levels: 1 2 3 4 5 6 7 8 9 10 11
>
> > as.factor(as.character(1:11))
>  [1] 1  2  3  4  5  6  7  8  9  10 11
> Levels: 1 10 11 2 3 4 5 6 7 8 9
>
> Regards,
> Iñaki
>
> > I would like it best when the sorting of split results stays the same no
> > matter the input (sorting of input == sorting of output)
> >
> > If that is not possibly a note of caution in the help pages and maybe an
> > example might be valuable.
> >
> >
> > Best, Peter
> >
> >         [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-devel at r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-devel
>

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