[Rd] Historical NA question

William Dunlap wdunlap at tibco.com
Tue May 6 21:36:52 CEST 2014


When does els%in%set give a different result than is.element(els,set)?
 I assumed they were copied form S+, where they are the same except
for argument names, but I may be wrong.
Bill Dunlap
TIBCO Software
wdunlap tibco.com


On Tue, May 6, 2014 at 12:23 PM, Hervé Pagès <hpages at fhcrc.org> wrote:
> On 05/06/2014 08:54 AM, William Dunlap wrote:
>>
>> You can also use is.element(els,set) instead of the equivalent
>> els%in%set
>
>
> No they are not *equivalent*. Equivalent means you could substitute
> one by the other in your code without changing its behavior.
>
> H.
>
>> and leave your precedence problems behind.
>> Bill Dunlap
>> TIBCO Software
>> wdunlap tibco.com
>>
>>
>> On Mon, May 5, 2014 at 10:35 PM, peter dalgaard <pdalgd at gmail.com> wrote:
>>>
>>>
>>> On 06 May 2014, at 01:05 , Hervé Pagès <hpages at fhcrc.org> wrote:
>>>
>>>>
>>>> BTW, that %in% has precedence over arithmetic operations is surprising,
>>>> error-prone, and doesn't cover any reasonable use case (who needs to
>>>> multiply the logical vector returned by %in% by some value?) but that's
>>>> another story:
>>>
>>>
>>> The point here is that the %foo% operators all have the _same_
>>> precedence. In principle, they can be user-coded, and there is no way to
>>> express what precedence is desirable. It may turn out slightly weird for
>>> %in%, but think of what would happen if %*% had lower precedence than
>>> addition.
>>>
>>> --
>>> Peter Dalgaard, Professor,
>>> Center for Statistics, Copenhagen Business School
>>> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
>>> Phone: (+45)38153501
>>> Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com
>>>
>>> ______________________________________________
>>> R-devel at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>
> --
> Hervé Pagès
>
> Program in Computational Biology
> Division of Public Health Sciences
> Fred Hutchinson Cancer Research Center
> 1100 Fairview Ave. N, M1-B514
> P.O. Box 19024
> Seattle, WA 98109-1024
>
> E-mail: hpages at fhcrc.org
> Phone:  (206) 667-5791
> Fax:    (206) 667-1319



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