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.
Try this:> f <- function(...) if (!is.null(list(...)$arg1)) cat("arg1 found\n") else cat("arg1 not found\n") > f(arg1 = 3)arg1 found> f(arg2 = 3)arg1 not found On 7/1/06, Gregor Gorjanc <gregor.gorjanc at gmail.com> wrote:> Hello! > > Say I have a function foo1, which has argument ... to pass various > arguments to foo2 i.e. > > foo1 <- function(x, ...) > { > foo2(x, ...) > } > > Say that foo2 accepts argument arg1 and I would like to do the following: > - if foo1 is called as foo1(x) then I would like to assign some value to > arg1 inside foo1 before calling foo2 > > arg1 <- "some value" > foo2(x, arg1=arg1) > > - if foo1 is called foo1(arg1="some other value") do not assign some > value to arg1 and call foo2 > > foo2(arg1=arg1) > > However, I am not able to do this since I do not know how to test/check > if arg1 was given in foo1. Is it possible to test whether some argument > was passed in "..." i.e. something like > > foo1 <- function(x, ...) > { > if(testForArgumentInThreeDots(arg1)) arg1 <- "some value" > foo2(x, arg1=arg1, ...) > } > > Thanks! > > -- > Lep pozdrav / With regards, > Gregor Gorjanc > > ---------------------------------------------------------------------- > University of Ljubljana PhD student > Biotechnical Faculty > Zootechnical Department URI: http://www.bfro.uni-lj.si/MR/ggorjan > Groblje 3 mail: gregor.gorjanc <at> bfro.uni-lj.si > > SI-1230 Domzale tel: +386 (0)1 72 17 861 > Slovenia, Europe fax: +386 (0)1 72 17 888 > > ---------------------------------------------------------------------- > "One must learn by doing the thing; for though you think you know it, > you have no certainty until you try." Sophocles ~ 450 B.C. > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel >
Gabor Grothendieck wrote:> Try this: > >> f <- function(...) if (!is.null(list(...)$arg1)) cat("arg1 found\n") >> else cat("arg1 not found\n") >> f(arg1 = 3) > arg1 found >> f(arg2 = 3) > arg1 not foundThanks! Use of list(...) really helps me here.> On 7/1/06, Gregor Gorjanc <gregor.gorjanc at 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 at 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.
Hi, Gabor Grothendieck wrote:> Try this: > >> f <- function(...) if (!is.null(list(...)$arg1)) cat("arg1 found\n") >> else cat("arg1 not found\n") >> f(arg1 = 3) > arg1 found >> f(arg2 = 3) > arg1 not foundActually it is not OK. Bellow is simplified example that shows, what I would like to do: foo1 <- function(x, ...) { if(is.null(list(...)$decreasing)) { decreasing <- TRUE } else { decreasing <- list(...)$decreasing } return(order(x, ..., decreasing=decreasing)) }> foo1(c(5, 2, 3, 4))[1] 1 4 3 2>foo1(c(5, 2, 3, 4), decreasing=FALSE)Error in order(x, ..., decreasing = decreasing) : formal argument "decreasing" matched by multiple actual arguments> On 7/1/06, Gregor Gorjanc <gregor.gorjanc at 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 at 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.
Bill Dunlap wrote:> On Sun, 2 Jul 2006, Gregor Gorjanc wrote: > >> Yes, this works. >> >> Thanks Gabor! >> >> Gabor Grothendieck wrote: >>> That's because you are passing the argument twice. Try this: >>> >>>> foo1 <- function(x, ...) >>> + { >>> + L <- list(...) >>> + if (is.null(L$decreasing)) L$decreasing <- TRUE >>> + do.call(order, c(list(x), L)) >>> + } >>>> foo1(c(5, 2, 3, 4), decreasing=FALSE) >>> [1] 2 3 4 1 > > How does this differ from > foo2 <- function(x, ..., decreasing=TRUE) > order(x, ..., decreasing = decreasing) > ?I agree, but I wanted to learn ... argument in a more general way. That was just an example - not a good one as you have showed.>> x<-c(5,2,3,4) >> identical(foo2(x), foo1(x)) > [1] TRUE >> identical(foo2(x,decreasing=F), foo1(x,decreasing=F)) > [1] TRUE >> identical(foo2(x,decreasing=T), foo1(x,decreasing=T)) > [1] TRUE-- 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.