Can the print() command in R be quieted?

I agree with hadley and mbq's suggestion of capture.output as the most general solution. For the special case of functions that you write (i.e., ones where you control the content), use message rather than print. That way you can suppress the output with suppressMessages.

print.and.return2 <- function() {
  message("foo")
  return("bar")
}

# Compare:
print.and.return2()
suppressMessages(print.and.return2())

If you absolutely need the side effect of printing in your own functions, why not make it an option?

print.and.return <- function(..., verbose=TRUE) {
  if (verbose) 
    print("foo")
  return("bar")
}


> print.and.return()
[1] "foo"
[1] "bar"
> print.and.return(verbose=FALSE)
[1] "bar"
> 

?capture.output

You may use hidden functional nature of R, for instance by defining function

deprintize<-function(f){
 return(function(...) {capture.output(w<-f(...));return(w);});
}

that will convert 'printing' functions to 'silent' ones:

noisyf<-function(x){
 print("BOO!");
 sin(x);
}

noisyf(7)
deprintize(noisyf)(7)
deprintize(noisyf)->silentf;silentf(7)