Not sure which one you want, but the following should cover it: R> f <- function(x) c(x=missing(x), y=exists("y")) R> f(1) x y FALSE FALSE R> f() x y TRUE FALSE R> y <- 1 R> f() x y TRUE TRUE R> f(1) x y FALSE TRUE
Andy From: Talbot Katz > > Hi. > > I'm having trouble testing for existence of an object inside > a function. > > Suppose I have a function: > > f<-function(x){ > ... > } > > and I call it with argument y: > > f(y) > > I'd like to check inside the function whether argument y > exists. Is this > possible, or do I have to either check outside the function > or pass the name > of the argument as a separate argument? > > If I do exists(x) or exists(eval(x)) inside the function and > y does not > exist, it generates an error message. If I do exists("x") it > says that x > exists even if y does not. If I had a separate argument to > hold the text > string "y" then I could check that. But is it possible to check the > existence of the argument inside the function without passing > its name as a > separate argument? > > Thanks! > > -- TMK -- > 212-460-5430 home > 917-656-5351 cell > > ______________________________________________ > 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. > > > ------------------------------------------------------------------------------ Notice: This e-mail message, together with any attachments,...{{dropped}} ______________________________________________ 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.