

   CChhaannggee tthhee PPrriinntt MMooddee ttoo IInnvviissiibbllee

        invisible(expr)

   VVaalluuee::

        This function returns a (temporarily) invisible copy of
        its argument.  This can be useful when it is desired to
        have functions return values which can be assigned, but
        which do not print when they are not assigned.

   SSeeee AAllssoo::

        `return' and `function'.

   EExxaammpplleess::

        # These functions both return their argument
        f1 <- function(x) x
        f2 <- function(x) invisible(x)
        f1(1)# prints
        f2(1)# does not

