Suppress output of a function

R only automatically prints the output of unassigned expressions, so just assign the result of the apply to a variable, and it won't get printed.

Use the capture.output() function. It works very much like a one-off sink() and unlike invisible(), it can suppress more than just print messages. Set the file argument to /dev/null on UNIX or NUL on windows. For example, considering Dirk's note:

> invisible(cat("Hi\n"))
Hi

> capture.output( cat("Hi\n"), file='NUL')
> 

It isn't clear why you want to do this without sink, but you can wrap any commands in the invisible() function and it will suppress the output. For instance:

1:10 # prints output
invisible(1:10) # hides it

Otherwise, you can always combine things into one line with a semicolon and parentheses:

{ sink("/dev/null"); ....; sink(); }

The following function should do what you want exactly:

hush=function(code){
  sink("NUL") # use /dev/null in UNIX
  tmp = code
  sink()
  return(tmp)
}

For example with the function here:

foo=function(){
  print("BAR!")
  return(42)
}

running

x = hush(foo())

Will assign 42 to x but will not print "BAR!" to STDOUT

Note than in a UNIX OS you will need to replace "NUL" with "/dev/null"