Hi,
The following function works, but is there a neater way to write it?
f = function(x,...)
{
# return a character vector of the arguments passed in after 'x'
gsub("
","",unlist(strsplit(deparse(substitute(list(...))),"[(,)]")))[-1]
}
> f(x,a,b,c*d)
[1] "a" "b" "c*d">
Thanks.
[[alternative HTML version deleted]]
Matthew Dowle <mdowle at concordiafunds.com> writes:> Hi, > > The following function works, but is there a neater way to write it? > > f = function(x,...) > { > # return a character vector of the arguments passed in after 'x' > gsub(" > ","",unlist(strsplit(deparse(substitute(list(...))),"[(,)]")))[-1] > } > > > f(x,a,b,c*d) > [1] "a" "b" "c*d" > >> f <- function(x,...)as.character(match.call(expand.dots=FALSE)$...) > f(x,a,b,c*d)[1] "a" "b" "c * d" or maybe f <- function(x,...) sapply(match.call(expand.dots=FALSE)$..., deparse, backtick=TRUE) -- O__ ---- Peter Dalgaard ?ster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
That's much neater, thanks.> -----Original Message----- > From: pd at pubhealth.ku.dk [mailto:pd at pubhealth.ku.dk] On > Behalf Of Peter Dalgaard > Sent: 02 March 2006 16:59 > To: Matthew Dowle > Cc: 'r-help at stat.math.ethz.ch' > Subject: Re: [R] Deparsing '...' > > > Matthew Dowle <mdowle at concordiafunds.com> writes: > > > Hi, > > > > The following function works, but is there a neater way to write it? > > > > f = function(x,...) > > { > > # return a character vector of the arguments passed in after 'x' > > gsub(" > > ","",unlist(strsplit(deparse(substitute(list(...))),"[(,)]")))[-1] > > } > > > > > f(x,a,b,c*d) > > [1] "a" "b" "c*d" > > > > > > > f <- function(x,...)as.character(match.call(expand.dots=FALSE)$...) > > f(x,a,b,c*d) > [1] "a" "b" "c * d" > > or maybe > > f <- function(x,...) > sapply(match.call(expand.dots=FALSE)$..., deparse, backtick=TRUE) > > > > > -- > O__ ---- Peter Dalgaard ?ster Farimagsgade 5, Entr.B > c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K > (*) \(*) -- University of Copenhagen Denmark Ph: > (+45) 35327918 > ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: > (+45) 35327907 >
f <- function(...) as.character(match.call())[-1]> f(x,a,b,c*d)[1] "x" "a" "b" "c * d" On Thu, 2 Mar 2006, Matthew Dowle wrote:> > Hi, > > The following function works, but is there a neater way to write it? > > f = function(x,...) > { > # return a character vector of the arguments passed in after 'x' > gsub(" > ","",unlist(strsplit(deparse(substitute(list(...))),"[(,)]")))[-1] > } > >> f(x,a,b,c*d) > [1] "a" "b" "c*d" >> > > Thanks.-- Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595
That's even neater. But when its called from within another function, this happens, see below. I was planning to call f something like 'getdots' and use it in several functions that need to do this.> f <- function(...) as.character(match.call())[-1] > f(a,b,c)[1] "a" "b" "c"> g = function(x,...) f(...) > g(x,a,b,c)[1] "..1" "..2" "..3"> -----Original Message----- > From: Prof Brian Ripley [mailto:ripley at stats.ox.ac.uk] > Sent: 02 March 2006 17:18 > To: Matthew Dowle > Cc: 'r-help at stat.math.ethz.ch' > Subject: Re: [R] Deparsing '...' > > > f <- function(...) as.character(match.call())[-1] > > f(x,a,b,c*d) > [1] "x" "a" "b" "c * d" > > On Thu, 2 Mar 2006, Matthew Dowle wrote: > > > > > Hi, > > > > The following function works, but is there a neater way to write it? > > > > f = function(x,...) > > { > > # return a character vector of the arguments passed in after 'x' > > gsub(" > > ","",unlist(strsplit(deparse(substitute(list(...))),"[(,)]")))[-1] > > } > > > >> f(x,a,b,c*d) > > [1] "a" "b" "c*d" > >> > > > > Thanks. > > -- > Brian D. Ripley, ripley at stats.ox.ac.uk > Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ > University of Oxford, Tel: +44 1865 272861 (self) > 1 South Parks Road, +44 1865 272866 (PA) > Oxford OX1 3TG, UK Fax: +44 1865 272595 >
That works well. So the final version is: getdots = function() as.character(match.call(sys.function(-1), call=sys.call(-1), expand.dots=FALSE)$...) Thank you both for your help.> -----Original Message----- > From: pd at pubhealth.ku.dk [mailto:pd at pubhealth.ku.dk] On > Behalf Of Peter Dalgaard > Sent: 02 March 2006 18:07 > To: Matthew Dowle > Cc: 'Prof Brian Ripley'; 'r-help at stat.math.ethz.ch' > Subject: Re: [R] Deparsing '...' > > > Matthew Dowle <mdowle at concordiafunds.com> writes: > > > That's even neater. But when its called from within > another function, > > this happens, see below. I was planning to call f something like > > 'getdots' and use it in several functions that need to do this. > > > > > f <- function(...) as.character(match.call())[-1] > > > f(a,b,c) > > [1] "a" "b" "c" > > > g = function(x,...) f(...) > > > g(x,a,b,c) > > [1] "..1" "..2" "..3" > > Yes, that will (and must) happen. If you really want to go > that route, you need something in the veins of > > > f <- function() match.call(sys.function(-1), call=sys.call(-1)) g = > > function(x,...) f() > > g(x,a,b,c) > g(x = x, a, b, c) > > > > > > -----Original Message----- > > > From: Prof Brian Ripley [mailto:ripley at stats.ox.ac.uk] > > > Sent: 02 March 2006 17:18 > > > To: Matthew Dowle > > > Cc: 'r-help at stat.math.ethz.ch' > > > Subject: Re: [R] Deparsing '...' > > > > > > > > > f <- function(...) as.character(match.call())[-1] > > > > f(x,a,b,c*d) > > > [1] "x" "a" "b" "c * d" > > > > > > On Thu, 2 Mar 2006, Matthew Dowle wrote: > > > > > > > > > > > Hi, > > > > > > > > The following function works, but is there a neater way > to write > > > > it? > > > > > > > > f = function(x,...) > > > > { > > > > # return a character vector of the arguments passed > in after 'x' > > > > gsub(" > > > > > ","",unlist(strsplit(deparse(substitute(list(...))),"[(,)]")))[-1] > > > > } > > > > > > > >> f(x,a,b,c*d) > > > > [1] "a" "b" "c*d" > > > >> > > > > > > > > Thanks. > > > > > > -- > > > Brian D. Ripley, ripley at stats.ox.ac.uk > > > Professor of Applied Statistics, > http://www.stats.ox.ac.uk/~ripley/ > > > University of Oxford, Tel: +44 1865 272861 (self) > > > 1 South Parks Road, +44 1865 272866 (PA) > > > Oxford OX1 3TG, UK Fax: +44 1865 272595 > > > > > > > ______________________________________________ > > R-help at stat.math.ethz.ch mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide! > > http://www.R-project.org/posting-guide.html > > > > -- > O__ ---- Peter Dalgaard ?ster Farimagsgade 5, Entr.B > c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K > (*) \(*) -- University of Copenhagen Denmark Ph: > (+45) 35327918 > ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: > (+45) 35327907 > >