Re: na=\"nil\" in ob-R.elo

[Brett Presnell]

I can verify that the :post work-around suggested by Chuck and
implemented by Jeremie works as advertised.

FWIW, I would certainly prefer to see the implementation
org-babel-R-write-object-command changed so that the work-around
wouldn't be necessary.

Thank you to both Chuck and Jeremie for looking into this.


Jeremie Juste <jeremiejuste@gmail.com> writes:

> [External Email]
>
> Hello,
>
> Thanks for the feedback
>
> || On Saturday, 16 Jan 2021 at 00:19, Berry, Charles" via "General 
> discussions about Org-mode. wrote:
>> You can use a :post header to customize outputs like this to make them
>> more pleasing. Or just use your own
>> `org-babel-R-write-object-command'.
>
>
> As a quick work around you can use
>
> #+name: remove-nil
> #+begin_src emacs-lisp :var tbl=""
>    (mapcar (lambda (row)
>              (mapcar (lambda (cell)
>                        (if (equal "nil" cell)
>                            ""
>                         cell))
>                      row))
>            tbl)
>
> #+end_src
>
>
>
> #+BEGIN_SRC R  :results value :colnames yes :post remove-nil[:colnames 
> yes](*this*)
> data.frame(A=c(NA,1,1,1,1),B=c(1,2,NA,4,4))
> #+end_src
>
> #+RESULTS:
> | A | B |
> |---+---|
> |   | 1 |
> | 1 | 2 |
> | 1 |   |
> | 1 | 4 |
> | 1 | 4 |
>
>
>
>>> Probably a silly question, but in ob-R.el, what is the reason for
>>> setting na=\"nil\" when defining org-babel-R-write-object-command?  Is
>>> this an elisp compatibility thing?
>>>
>>
>> I don't get it either. The value corresponding to the NA becomes a string in 
>> emacs-lisp whether \"nil\" or \"\" is used.
>> So when passed to elisp via a :post header referencing an emacs-lisp
>> src block, its treated as a string.
>
> Thanks Chuck for pointing this out. R users are used to handle NA but in
> this particular case where empty string and NA are treated
> the same, I'm not sure the nil feature is very useful. If it does not break
> anything else I will consider removing it.
>
>
> Best regards,