[R] Problem with cat() == A related question

[Martin Maechler]

>>>>> William Revelle <lists at revelle.net>
>>>>>     on Tue, 14 Sep 2010 14:52:32 -0500 writes:

    > At 3:45 PM -0400 9/14/10, jim holtman wrote:
    >> The problem is the 'cat' enclosing the 'print'; just get rid of the
    >> 'cat' -- that is what is causing the extra output
    >> 
    >> On Tue, Sep 14, 2010 at 3:34 PM, Peng, C <cpeng.usm at gmail.com> wrote:
    >>> 
    >>> It is still visible even it is set invisible(NULL):
    >>> 
    >>>> fn1 <- function(n = 5){
    >>> +  mat <- matrix(rnorm(5*5), 5, 5)
    >>> +   cat(print(mat))
    >>> +  invisible(NULL)}
    >>>> fn1()
    >>> [,1]        [,2]       [,3]        [,4]       [,5]
    >>> [1,] -1.22767085 -1.41468587 -2.0156231  0.29732942  0.5755600
    >>> [2,] -0.16775996 -0.03780596 -0.9461079  0.91289175  0.1254273
    >>> [3,]  0.09696032 -0.75522210 -0.7494442 -0.21341669  1.7088194
    >>> [4,]  0.13535505 -1.09011005 -0.6074198  0.05342614 -1.1996344
    >>> [5,]  0.66474083 -2.62206248  0.1329972  0.06132865  0.5124778
    >>> -1.227671 -0.1677600 0.09696032 0.1353550 0.6647408 -1.414686 -0.03780596
    >>> -0.7552221 -1.09011 -2.622062 -2.015623 -0.9461079 -0.7494442 -0.6074198
    >>> 0.1329972 0.2973294 0.9128917 -0.2134167 0.05342614 0.06132865 0.57556
    >>> 0.1254273 1.708819 -1.199634 0.5124778>
    >>>> 
    >>> --
    >>> View this message in context: 
    >>> http://r.789695.n4.nabble.com/Problem-with-cat-tp2538811p2539551.html
    >>> Sent from the R help mailing list archive at Nabble.com.
    >>> 


    > I think that what Peng was trying to do was print it without the 
    > column and row names

    >> mat <-  matrix(1:25,5,5)
    >> colnames(mat) <- rownames(mat) <- rep("",5)
    >> print(mat)
              
    > 1  6 11 16 21
    > 2  7 12 17 22
    > 3  8 13 18 23
    > 4  9 14 19 24
    > 5 10 15 20 25

Yes.

A (slightly more general and efficient) version is

 > sfsmisc::empty.dimnames( matrix(1:40, 5,8) )

  1  6 11 16 21 26 31 36
  2  7 12 17 22 27 32 37
  3  8 13 18 23 28 33 38
  4  9 14 19 24 29 34 39
  5 10 15 20 25 30 35 40
 > 

--- where the  empty.dimnames() function is just one small reason to
  get the "sfsmisc" package ;-)

Martin Maechler,
ETH Zurich