How do you print to stderr in R?

Question

How do you print to stderr in R?

This would especially useful for scripts written in Rscript.

Answer 1

Here's a more flexible version for debugging/verbose use in Rscript. Not only it prints to stderr as you ask, but it also allows you to pass variable number of arguments, types etc, like printf does.

v <- function(...) cat(sprintf(...), sep='', file=stderr())

Now one can do things like:

v("name: %s  age: %d\n", name, age)

etc.