[R] Quantiles with ordered categories
maechler at stat.math.ethz.ch
Thu Mar 16 18:25:29 CET 2017
>>>>> <matthias-gondan at gmx.de>
>>>>> on Tue, 14 Mar 2017 21:54:42 +0100 writes:
> I found it:
> quantile(ordered(1:10), probs=0.5, type=1)
> works, because type=1 seems to round up or down, whatever. The default option for is 7, which wants to interpolate, and then produces the error.
> Two options come to my mind:
> - The error message could be improved.
> - The default type could be 1 if the data is from ordered categories.
> - Or both.
Well, it is remarkable that nobody looks at the help page (or
the source code) of quantile() to be informed.
In 'Details' it has contained
Types 1 and 3 can be used for class; "Date" and for ordered factors.
since Oct 15, 2009 ...
But I agree that the error message can be improved and have done
so now, so that instead of
"factors are not allowed"
you now get
"'type' must be 1 or 3 for ordered factors"
> It is probably a little thing to fix, but I lack the skills to do this myself.
(Really? -- After seeing the change you will agree it was easy .. ?)
Thank you for the suggestion.
> Best wishes,
> Von: Bert Gunter
> Gesendet: Dienstag, 14. März 2017 21:34
> An: matthias-gondan at gmx.de
> Cc: r-help at r-project.org
> Betreff: Re: [R] Quantiles with ordered categories
> Bert Gunter
> "The trouble with having an open mind is that people keep coming along
> and sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
> On Tue, Mar 14, 2017 at 12:36 PM, <matthias-gondan at gmx.de> wrote:
>> Dear R users,
>> This works:
>> quantile(1:10, probs=0.5)
>> This fails (obviously):
>> quantile(factor(1:10), probs=0.5)
>> But why do quantiles for ordered factors not work either?
>> quantile(ordered(1:10), probs=0.5)
>> Is it because interpolation (see the optional type argument) is not defined?
> Is there an elegant workaround?
> No. How can there be? By definition, all that is assumed by an ordered
> factor is an ordering of the categories. How can you "interpolate" in
> ordered(letters[1:3]) . ASAIK there is no "a.5" .
> -- Bert
>> Thank you.
>> Best wishes,
>> [[alternative HTML version deleted]]
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