Another one here, I updated with nadvice.el.
1. Normal Evaluation
Now, We have normal evaluation and results here.
#+begin_src R :results value
c('a','b','c')
#+end_src
#+RESULTS:
| a |
| b |
| c |
2. Function Override
You can override temporary org-babel-R-process-value-result
in ob-R.el by C-c C-c
the following code.
#+BEGIN_SRC emacs-lisp :results value
(defun org-babel-R-process-value-result-transpose (result column-names-p)
(apply #'mapcar* #'list result))
(advice-add 'org-babel-R-process-value-result
:override #'org-babel-R-process-value-result-transpose)
#+END_SRC
3. Transposed evaluation
Hereafter, every result of R evaluation will be transposed.
#+begin_src R :results value
c('a','b','c')
#+end_src
#+RESULTS:
| a | b | c |
4. Remove Function Override
You have to redefine back by C-c C-c
the following code for normal org-mode operation.
#+BEGIN_SRC emacs-lisp :results value
(advice-remove 'org-babel-R-process-value-result
#'org-babel-R-process-value-result-transpose)
#+END_SRC
5. Normal Evaluation
Results are in normal operation now.
#+begin_src R :results value
c('a','b','c')
#+end_src
#+RESULTS:
| a |
| b |
| c |
It will be useful if you evaluate whole org-mode document by C-c C-v C-b
(M-x org-babel-execute-buffer
).