R help - Jan 2005 - How to quieten axis() for Sweave: avoid echoing NULL?

Dear R-community,

I'm using Sweave to produce reports.  The reports require the
"axis"
command.  When I run axis the program returns NULL as well as creating
the axis.  
> plot(1:4, rnorm(4), axes=FALSE)
> axis(1, 1:4, LETTERS[1:4])
NULL
>
So, my Sweave tex files have 

\begin{Schunk}
\begin{Soutput}
NULL
\end{Soutput}
\end{Schunk}

in front of each graphic that requires axis.  I can easily find them
and remove them, but I was wondering: is it something I can avoid?  Or
am I doing something foolish and obvious?

Thanks for any assistance,

Andrew
-- 
Andrew Robinson                      Ph: 208 885 7115
Department of Forest Resources       Fa: 208 885 6226
University of Idaho                  E : andrewr at uidaho.edu
PO Box 441133                        W : http://www.uidaho.edu/~andrewr
Moscow ID 83843                      Or: http://www.biometrics.uidaho.edu
No statement above necessarily represents my employer's opinion.

Hi!

The following works for me:

\begin{figure}
\centering
<<fig1.R,fig=true,echo=false>>plot(1:4, rnorm(4), axes=FALSE)
axis(1, 1:4, LETTERS[1:4])
@
\caption{Plot test}
\label{fig:1}
\end{figure}

I'm using R 2.0.1 on an i686 with GNU/Linux Ubuntu 4.10.

Andrew Robinson wrote:
> Dear R-community,
> 
> I'm using Sweave to produce reports.  The reports require the
"axis"
> command.  When I run axis the program returns NULL as well as creating
> the axis.  
> 
> 
>>plot(1:4, rnorm(4), axes=FALSE)
>>axis(1, 1:4, LETTERS[1:4])
> 
> NULL
> 
> 
> So, my Sweave tex files have 
> 
> \begin{Schunk}
> \begin{Soutput}
> NULL
> \end{Soutput}
> \end{Schunk}
> 
> in front of each graphic that requires axis.  I can easily find them
> and remove them, but I was wondering: is it something I can avoid?  Or
> am I doing something foolish and obvious?
> 
> Thanks for any assistance,
> 
> Andrew
---
Ulises M. Alvarez
<umalvarez at fata.unam.mx>

Andrew Robinson <andrewr at uidaho.edu> writes:
> Dear R-community,
> 
> I'm using Sweave to produce reports.  The reports require the
"axis"
> command.  When I run axis the program returns NULL as well as creating
> the axis.  
> 
> > plot(1:4, rnorm(4), axes=FALSE)
> > axis(1, 1:4, LETTERS[1:4])
> NULL
> >
> 
> So, my Sweave tex files have 
> 
> \begin{Schunk}
> \begin{Soutput}
> NULL
> \end{Soutput}
> \end{Schunk}
> 
> in front of each graphic that requires axis.  I can easily find them
> and remove them, but I was wondering: is it something I can avoid?  Or
> am I doing something foolish and obvious?
I think this qualifies as a bug along with similar issues with
title(), text(), and mtext(). They all end with .Internal calls
producing NULL. Once upon a time, they did so invisibly, but somehow
this changed.

The simple workaround is to wrap the call in invisible().

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907