Test for argument in ...

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)
?

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