R help - Mar 2003 - Suppressing row labels.

Very often when I print a data frame (particularly when sink()-ing to
a file I do NOT want the row labels (which are in such cases usually
1, 2, ... nrow(x), where x is the data frame in question).  I can of
course edit these out ``by hand'', but that's a bit of a pain in the
pohutukawa.

I recently discovered (reading the help on print.data.frame
meticulously, and following it through to print.matrix) that
I CAN suppress these row names by executing, e.g.

	> print(x,rowlab=rep("",nrow(x)))

However it would be ever-so-slightly nicer (require somewhat fewer
key strokes) if there were an option to print.data.frame that would
allow suppression of row names.  E.g. an argument ``srn=FALSE''.
(Where ``srn'' stands for ``suppress row names''.)

I have written my own simple minded implementation of this option,
given below in case anyone else out there may have shared my
frustration at being unable to figure out how to suppress row names.

I would ask that the R developers consider including an argument like
unto this in a future release.

On a related note:  I would also like, generally speaking, NOT to
have row names included in LaTeX tables that I create from data
frames or matrices.  As far as I can discern, none of the currently
available LaTeX-ing functions provide the option of suppressing the
row names.  The functions I've looked at are:

	o xtable{xtable}
	o latex.table{quantreg}
	o latex{Hmisc}

It would be nice (said he wistfully) if the developers of at
least one of these packages would consider adding such an option.


					cheers,

						Rolf Turner

===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+==Code
for my mild revision of print.data.frame:
===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+==print.data.frame
<- function (x, ..., digits = NULL, quote = FALSE,
                              right = TRUE, srn=FALSE)
{
    if (length(x) == 0) {
        cat("NULL data frame with", length(row.names(x)),
"rows\n")
    }
    else if (length(row.names(x)) == 0) {
        print.default(names(x), quote = FALSE)
        cat("<0 rows> (or 0-length row.names)\n")
    }
    else {
        if (!is.null(digits)) {
            op <- options(digits = digits)
            on.exit(options(op))
        }
        rowlab <- if(srn) rep("",nrow(x)) else row.names(x)
        print.matrix(format(x), rowlab=rowlab, ..., quote = quote,
                     right = right)
    }
    invisible(x)
}
===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===

>>>>> "Rolf" == Rolf Turner <rolf@math.unb.ca>
>>>>>     on Thu, 6 Mar 2003 15:42:51 -0400 (AST) writes:
I think this definitely belongs to the R-devel mailing list
-- to which I'm diverting it now.

    Rolf> Very often when I print a data frame (particularly when sink()-ing
to
    Rolf> a file I do NOT want the row labels (which are in such cases
usually
    Rolf> 1, 2, ... nrow(x), where x is the data frame in question).  I can
of
    Rolf> course edit these out ``by hand'', but that's a bit of
a pain in the
    Rolf> pohutukawa.

    Rolf> I recently discovered (reading the help on print.data.frame
    Rolf> meticulously, and following it through to print.matrix) that
    Rolf> I CAN suppress these row names by executing, e.g.

    >> print(x,rowlab=rep("",nrow(x)))

    Rolf> However it would be ever-so-slightly nicer (require somewhat fewer
    Rolf> key strokes) if there were an option to print.data.frame that would
    Rolf> allow suppression of row names.  E.g. an argument
``srn=FALSE''.
    Rolf> (Where ``srn'' stands for ``suppress row names''.)

Alternatively, I'd prefer allowing  rowlab = ""
which looks nice enough and doesn't need a new argument

BTW: You've helped uncovering a problem in R-devel: 
  There, `rowlab' and `collab' are currently silently not working  :
  print.matrix() doesn't have them anymore, only prmatrix() does
  {which is not the same any more}

 -- hmm...

    Rolf> I have written my own simple minded implementation of this option,
    Rolf> given below in case anyone else out there may have shared my
    Rolf> frustration at being unable to figure out how to suppress row
names.

The drawback of such an approach is that you need explicit
print(.) calls (which may look a bit ugly).
An alternative approach is to use default printing for a new
object made from the original one --- though I must admit I'm
not 100% convinced it's appropriate for your original proposal:

Relatedly (but not identically aimed), I have had an alternative
implemented from an S-news "discussion" including Bill Venables
of about 1993. 

The way it's here, it's not working for data frames (just for
matrices, but also other arrays), also since data frames must
have unique row names by definition.
But you get the main idea :

empty.dimnames <- function(a)
{
  ## 'Remove' all dimension names from an array for compact printing.
  d <- list(); l <- 0
  for(i in dim(a)) d[[l <- l + 1]] <- rep("", i)
  dimnames(a) <- d
  a
}

with help :
-------------------------------------------------------------------------

empty.dimnames            package:sfsmisc            R Documentation

Empty Dimnames of an Array.

Description:

     `Remove' all dimension names from an array for compact printing.

Usage:

     empty.dimnames(a)

Arguments:

       a: an `array', especially a matrix.

Value:

     Returns `a' with its dimnames replaced by empty character strings.

Author(s):

     Bill Venables / Martin Maechler, Sept 1993.

See Also:

     `unname' removes the dimnames.

Examples:

     empty.dimnames(diag(5)) # looks much nicer

     (a <- matrix(-9:10, 4,5))
     empty.dimnames(a) # nicer, right?

-------------------------------------------------------------------------