[Rd] Possible bug in factor (PR#531)
maechler@stat.math.ethz.ch
maechler@stat.math.ethz.ch
Wed, 3 May 2000 09:39:06 +0200 (MET DST)
>>>>> "PD" == Peter Dalgaard BSA <p.dalgaard@biostat.ku.dk> writes:
PD> Thomas Lumley <thomas@biostat.washington.edu> writes:
>> In this particular case you know that x has class
>> c("ordered","factor") and that you want it to have class "factor",
>> so it is harmless. It still may be unnecessary -- eg if you just
>> want it to have treatment contrasts rather than polynomial contrasts
>> you can use C() or constrasts()<-.
PD> We do have a problem in the documentation:
PD> The default for factor is ordered=FALSE according to the help page
PD> but
>> factor(ordered(4:1),ordered=F)
PD> [1] 4 3 2 1 Levels: 1 2 3 4
>> factor(ordered(4:1))
PD> [1] 4 3 2 1 Levels: 1 < 2 < 3 < 4
PD> and the actual function definition says
PD> function (x, levels = sort(unique(x), na.last = TRUE),
PD> labels=levels, exclude = NA, ordered = is.ordered(x))
I've fixed the docu for "r-release" [1.0.2 if ever].
BTW: A branch merge would come handy...
(should I try, using instructions on the R-developers' page?)
Martin
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