It is not clear to me exactly what you are looking to do, but if you are trying to check whether an argument has been passed via ..., I have used this convention before.
fun <- function(arg, ...) { opts <- list(...) if('opt' %in% names(opts)) # Do something... } Does that help? -------------------------------------- Jonathan P. Daily Technician - USGS Leetown Science Center 11649 Leetown Road Kearneysville WV, 25430 (304) 724-4480 "Is the room still a room when its empty? Does the room, the thing itself have purpose? Or do we, what's the word... imbue it." - Jubal Early, Firefly r-help-boun...@r-project.org wrote on 03/29/2011 01:47:41 PM: > [image removed] > > [R] passing arguments via "..." > > Cable, Samuel B Civ USAF AFMC AFRL/RVBXI > > to: > > r-help > > 03/29/2011 01:51 PM > > Sent by: > > r-help-boun...@r-project.org > > I would like to do something like the following: > > Fancyhist<-function(x,...) { > > # first, process x into xprocess somehow, then ... > > if (is.null(breaks)) { # yes, I know this is wrong > # define the histogram breaks somehow, then call hist: > hist(xprocess,breaks=breaks,...) > } else { > # use breaks give in calling argument > hist(xprocess,...) > } > > } > > But, those of you who know R better than I do have already spotted that > "is.null(breaks)" just won't work. Neither does "exists" or "missing". > > I can think of ways to do this involving new arguments with new names -- > like "histbreaks" or something -- but that seems inelegant. > > Is there a way to do what I am trying to do here? > > Thanks. > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.