[R] R2HTML output shows NULL

[Greg Snow]

Joshua,

The task call back mechanism passes on a flag to say if the output was
invisible or not, so the HTML functions would just need to look for
and honor that flag.  This is what the TeachingDemos versions do.

On Fri, Apr 27, 2012 at 4:07 PM, Joshua Wiley <jwiley.psych at gmail.com> wrote:
> On Fri, Apr 27, 2012 at 2:52 PM, Greg Snow <538280 at gmail.com> wrote:
>> Jeff, there are also many times that people are told not to post HTML,
>> so this case would be a bit of a Catch 22.  Also some of us (well me
>> at least, I expect others have as well) have experienced this already
>> and fully understand what is being discussed without needing an
>> example (and for this case I don't know that those who don't already
>> understand what she is saying would benefit much from the example
>> without the output).
>>
>> Erin,
>>
>> I have seen the same thing (as well as all the output from the hist
>> function being printed and other things that are usually invisible)
>> and have not found a way to suppress/hide the usually invisible
>> output.
>
> I have struggled with this for some time.  (embarrassingly, I
> filed/assigned myself a bug report over 6 months ago) you can track
> the status here:
> https://r-forge.r-project.org/tracker/index.php?func=detail&aid=1628&group_id=405&atid=1643
>
> It seems like there should be two solutions: A) somehow never grab
> output that was meant to be invisible B) grab but then parse out such
> output.  It is not too difficult to alter the internals of R2HTML to
> not print NULLs, but at least the easy way is global.  I.e., any code
> output that is only NULL is simply dropped, even though sometimes
> there are legitimate cases.  This is essentially the latter approach
> where there are the NULLs but clever printing avoids printing them.  I
> have not had enough time to fully grasp the underlying workings of how
> output is redirected and stored.  If anyone has suggestions, I would
> be happy to hear them.  If anyone knows of nice guides/suggested
> reading about how Sweave or the like work in R, I would also be
> interested.  Everytime I have gone straight to the source code, I lose
> sight of the forest for the trees =\
>
> I have not forgotten or stopped working on it, but I was not the
> original package author so I have a lot to learn about how it works
> and I am swamped with classes and research presently so progress is
> slow.
>
> Josh
>
>
>
>
>
>>
>> An alternative is the txtStart and friends functions in the
>> TeachingDemos package (which were inspired by, but not as fancy as,
>> the R2HTML package).  Like R2HTML those functions will copy your
>> session to a file (currently plain text, enhanced text (can be post
>> processed with the enscript program to provide color and embedded
>> graphics), or MS Word documents (via the R2wd package), .rtf files
>> (via the rtf package) are planned).  These functions by default do not
>> include output that is returned invisibly.
>>
>> On Fri, Apr 27, 2012 at 2:06 PM, Jeff Newmiller
>> <jdnewmil at dcn.davis.ca.us> wrote:
>>> Haven't you been asked to provide an example of code that illustrates your problem often enough by now to anticipate the request in your first post?
>>> ---------------------------------------------------------------------------
>>> Jeff Newmiller                        The     .....       .....  Go Live...
>>> DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live Go...
>>>                                      Live:   OO#.. Dead: OO#..  Playing
>>> Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
>>> /Software/Embedded Controllers)               .OO#.       .OO#.  rocks...1k
>>> ---------------------------------------------------------------------------
>>> Sent from my phone. Please excuse my brevity.
>>>
>>> Erin Hodgess <erinm.hodgess at gmail.com> wrote:
>>>
>>>>Hello R People:
>>>>
>>>>I am using the R2HTML program for the first time (actually yesterday),
>>>>and I have a question, please:
>>>>
>>>>I am getting NULL in the webpage in several places, presumably where
>>>>NULL would appear on the screen.
>>>>
>>>>How would I go about fixing that, please?
>>>>
>>>>Thanks,
>>>>Erin
>>>>
>>>>
>>>>--
>>>>Erin Hodgess
>>>>Associate Professor
>>>>Department of Computer and Mathematical Sciences
>>>>University of Houston - Downtown
>>>>mailto: erinm.hodgess at gmail.com
>>>>
>>>>______________________________________________
>>>>R-help at r-project.org mailing list
>>>>https://stat.ethz.ch/mailman/listinfo/r-help
>>>>PLEASE do read the posting guide
>>>>http://www.R-project.org/posting-guide.html
>>>>and provide commented, minimal, self-contained, reproducible code.
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
>>
>> --
>> Gregory (Greg) L. Snow Ph.D.
>> 538280 at gmail.com
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
>
>
> --
> Joshua Wiley
> Ph.D. Student, Health Psychology
> Programmer Analyst II, Statistical Consulting Group
> University of California, Los Angeles
> https://joshuawiley.com/



-- 
Gregory (Greg) L. Snow Ph.D.
538280 at gmail.com