I'll be glad to add it to the gtools package if it doesn't (immediately) go
into one of the core packages.
Sent from my iPhone
On Jul 26, 2012, at 7:35 AM, "Bert Gunter" <gunter.ber...@gene.com> wrote:
> Indeed!
>
> -- Bert
>
> On Wed, Jul 25, 2012 at 3:59 PM, David Winsemius <dwinsem...@comcast.net>
> wrote:
>>
>> On Jul 24, 2012, at 4:39 PM, Bert Gunter wrote:
>>
>>> Folks:
>>>
>>> Herein is a suggestion for a little R convenience function mainly to
>>> obtain unevaluated ... function arguments. It arose from a query on
>>> R-help on how to get these arguments. The standard (I think) idiom to
>>> do this is via
>>>
>>> match.call(expand.dots=FALSE)$...
>>>
>>> However, Bill Dunlap pointed out that this repeats the argument
>>> matching of the function call and suggested a couple of alternatives
>>> that do not, one of which I've adapted as the following function,fun
>>> (I'll comment on naming in a second):
>>>
>>> fun <- as.list(substitute((...), env = parent.frame()))[-1]
>>
>>
>> I think instead:
>>
>> fun <- function() as.list(substitute((...), env = parent.frame()))[-1]
>>
>> --
>> David.
>>>
>>>
>>> Typical usage would be:
>>>
>>> f <- function(x, ...,y)fun()
>>>
>>> e.g.
>>>
>>>> f(x = 5,z=sin(a),y=3,stop("oh"),w=warning("Yikes"))
>>>
>>> $z
>>> sin(a)
>>>
>>> [[2]]
>>> stop("oh")
>>>
>>> $w
>>> warning("Yikes")
>>>
>>> It turns out that (surprisingly to me) the substitute idiom is faster
>>> than the match.call idiom, although the difference appears
>>> unimportant, since both are so fast. And it is a little slower when
>>> wrapped into a function, anyway -- I wasn't able to figure out a
>>> convenient way to wrap the match.call version into a function.
>>>
>>> The question is where -- if anywhere -- should this little one-liner
>>> go? Seems to me that there are 3 possibilities:
>>> 1. Nowhere. Unnecessary and trivial. An entirely reasonable response,
>>> imho; I leave it to guRus to make this judgment.
>>>
>>> 2. In with match.call(); in which case a name like match.dots would
>>> seem appropriate.
>>>
>>> 3. In with substitute(); in which case something like substituteDots
>>> to make the relationship clear might be appropriate.
>>>
>>> If R core or others do want to use this, I would be happy to write the
>>> line or two of additional documentation required (if no one else wants
>>> to).
>>>
>>> And to repeat... I know this is trivial, so no explanation or response
>>> is needed if it is decided to ignore it.
>>>
>>> Best,
>>> Bert
>>>
>>>
>>>
>>>
>>> --
>>>
>>> Bert Gunter
>>> Genentech Nonclinical Biostatistics
>>>
>>> Internal Contact Info:
>>> Phone: 467-7374
>>> Website:
>>>
>>> http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
>>>
>>> ______________________________________________
>>> R-devel@r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>>
>> David Winsemius, MD
>> Heritage Laboratories
>> West Hartford, CT
>>
>
>
>
> --
>
> Bert Gunter
> Genentech Nonclinical Biostatistics
>
> Internal Contact Info:
> Phone: 467-7374
> Website:
> http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
>
> ______________________________________________
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
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