suppress messages displayed by “print” instead of “message” or “warning” in R

Question

Many R packages I work with involve functions that give all their messages and warnings through commands to print() calls rather than commands to message() or warning(). I'd like to be able to silence these functions progress indicators, etc, but the standard supressWarnings() or supressMessages doesn't do it. Is there a way I can just suppressPrint?

For example:

silly_developer_function <- function(x){
   print("Thanks for using my function!!")
   if(is(x, "numeric"))
     print("warning, x should be a character")
   x
}

I'd like to have a simple function suppressPrint() that I could wrap around a call to this function that would suppress the warning and useless messages (but still print the return value).

Answer 1

Well, those packages are buggy to start with. Use of print() for anything but side-effect in print implementations is a serious mistake.

That said, you can simply use capture.output() to collect the output from such code instead of printing it. So for the above it would be

capture.output(x <- silly_developer_function(...))
print(x)

Answer 2

Another hacky way is to override the default print function. It will affect some functionality, such as printing the body of functions, but objects with their own print methods still get returned as usual.

print <- function(...) {}

> silly_developer_function("a")
[1] "a"
> silly_developer_function(1)
[1] 1