First define a function which is like list() except it ignores all NULL components. Using that we can write:
list.wo.null <- function(...) list(...)[!sapply(list(...), is.null)] library(lattice) myhist <- function(limits) do.call("histogram", list.wo.null(~ height, singer, endpoints = if (!missing(limits)) limits)) } myhist() myhist(c(0, 100)) On 5/27/07, David Lindelof <[EMAIL PROTECTED]> wrote: > Dear userRs, > > Is there a way to explicitly set an argument to a function call as > missing? > > E.g., > > histogram(foo, > bar, > endpoints=ifelse(!missing(limits),limits,NA/NULL/whatever))) > > In this call I want to set a value to the endpoints argument only if the > `limits' variable has been set, and leave the defaults otherwise. > > The only way I could do it is thus: > > if (!missing(limits)) histogram(foo,bar,endpoints=limits) > else histogram(foo,bar) > > Is there a cleaner way? > > Kind regards, > > David Lindelof > > ______________________________________________ > R-help@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 > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@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 and provide commented, minimal, self-contained, reproducible code.