[Rd] 'ordered' destroyed to 'factor'

"Jens Oehlschlägel" jens.oehlschlaegel at truecluster.com
Sun Jun 18 12:34:11 CEST 2017

Defending the status quo misses the point that R *could* handle ordinal data with a fixed set of levels but actually *does not*. Although it would be useful. Even if this does not imply to handle any possible straw-man situations. Having data-types for nominal, ordinal, and interval-scale data is - in theory - one of the major advantages of S over SAS. But *having* without *handling* means: only in theory, not in practice. Has r-devel really lost the momentum for continuous improvement, to converge R to an optimum? I struggle to recognize the project I loved in 2000.

Gesendet: Freitag, 16. Juni 2017 um 18:31 Uhr
Von: "peter dalgaard" <pdalgd at gmail.com>
An: "Robert McGehee" <rmcgehee at walleyetrading.net>
Cc: "Jens Oehlschlägel" <jens.oehlschlaegel at truecluster.com>, "r-devel at r-project.org" <r-devel at r-project.org>
Betreff: Re: [Rd] 'ordered' destroyed to 'factor'
> On 16 Jun 2017, at 15:59 , Robert McGehee <rmcgehee at walleyetrading.net> wrote:
> For instance, what would you expect to get from unlist() if each element of the list had different levels, or were both ordered, but in a different way, or if some elements of the list were factors and others were ordered factors?
>> unlist(list(ordered(c("a","b")), ordered(c("b","a"))))
> [1] ?

Those actually have the same levels in the same order: a < b

Possibly, this brings the point home more clearly

unlist(list(ordered(c("a","c")), ordered(c("b","d"))))

(Notice that alphabetical order is largely irrelevant, so all of these level orderings are equally possible:

a < c < b < d
a < b < c < d
a < b < d < c
b < a < c < d
b < a < d < c
b < d < a < c


Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com


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