Re: [Rd] Test for argument in ...

From: Gregor Gorjanc <gregor.gorjanc_at_gmail.com>
Date: Sun 02 Jul 2006 - 02:17:42 GMT

Gabor Grothendieck wrote:

> Try this:
> 

>> f <- function(...) if (!is.null(list(...)$arg1)) cat("arg1 found\n")
>> else cat("arg1 not found\n")
>> f(arg1 = 3)
> arg1 found

>> f(arg2 = 3)
> arg1 not found

Thanks!

Use of list(...) really helps me here.

> On 7/1/06, Gregor Gorjanc <gregor.gorjanc@gmail.com> wrote:

>> Hello!
>>
>> Say I have a function foo1, which has argument ... to pass various
>> arguments to foo2 i.e.
>>
>> foo1 <- function(x, ...)
>> {
>> foo2(x, ...)
>> }
>>
>> Say that foo2 accepts argument arg1 and I would like to do the following:
>> - if foo1 is called as foo1(x) then I would like to assign some value to
>> arg1 inside foo1 before calling foo2
>>
>> arg1 <- "some value"
>> foo2(x, arg1=arg1)
>>
>> - if foo1 is called foo1(arg1="some other value") do not assign some
>> value to arg1 and call foo2
>>
>> foo2(arg1=arg1)
>>
>> However, I am not able to do this since I do not know how to test/check
>> if arg1 was given in foo1. Is it possible to test whether some argument
>> was passed in "..." i.e. something like
>>
>> foo1 <- function(x, ...)
>> {
>> if(testForArgumentInThreeDots(arg1)) arg1 <- "some value"
>> foo2(x, arg1=arg1, ...)
>> }
>>
>> Thanks!
>>
>> --
>> Lep pozdrav / With regards,
>> Gregor Gorjanc
>>
>> ----------------------------------------------------------------------
>> University of Ljubljana PhD student
>> Biotechnical Faculty
>> Zootechnical Department URI: http://www.bfro.uni-lj.si/MR/ggorjan
>> Groblje 3 mail: gregor.gorjanc <at> bfro.uni-lj.si
>>
>> SI-1230 Domzale tel: +386 (0)1 72 17 861
>> Slovenia, Europe fax: +386 (0)1 72 17 888
>>
>> ----------------------------------------------------------------------
>> "One must learn by doing the thing; for though you think you know it,
>> you have no certainty until you try." Sophocles ~ 450 B.C.
>>
>> ______________________________________________
>> R-devel@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
-- 
Lep pozdrav / With regards,
    Gregor Gorjanc

----------------------------------------------------------------------
University of Ljubljana     PhD student
Biotechnical Faculty
Zootechnical Department     URI: http://www.bfro.uni-lj.si/MR/ggorjan
Groblje 3                   mail: gregor.gorjanc <at> bfro.uni-lj.si

SI-1230 Domzale             tel: +386 (0)1 72 17 861
Slovenia, Europe            fax: +386 (0)1 72 17 888

----------------------------------------------------------------------
"One must learn by doing the thing; for though you think you know it,
 you have no certainty until you try." Sophocles ~ 450 B.C.

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Received on Sun Jul 02 12:20:03 2006

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