Re: org-babel: Why isn't =:results value= working with (my) python?

[Dan Davison <davison@stats.ox.ac.uk>]

"Thomas S. Dye" <tsd@tsdye.com> writes:

> On Feb 4, 2010, at 5:06 AM, Scott May wrote:
>
>
>     Using org-babel, the following example produces no output for me when I
>     execute using C-c C-c:
>
>     #+begin_src python :results value
>     2 + 2
>     #+end_src
>
>     #+results:
>     : None
>
>     In my messages buffer I see the following:
>
>     : (Shell command succeeded with no output)
>
>     Now the equivalent emacs-lisp example does work:
>
>     #+begin_src emacs-lisp :results value
>     (+ 2 2)
>     #+end_src
>
>     #+results:
>     : 4
>
>     Furthermore,
>
>     #+begin_src python :results output
>     print(2 + 2)
>     #+end_src
>
>     #+results:
>     : 4
>
>     works as expected.
>
>     Am I missing something obvious? Is the problem with my python setup, or
>     perhaps org-babel-python?
>
>     I have tested this on both my Windows and Ubuntu setups. I am using org
>     version 6.34trans.
>
>     Cheers,
>     Scott
>
>
>
> Hi Scott,
>
> You need :session.

Or, if you are going to stick with the default non-session evaluation,
you need to include a return statement:

#+begin_src python :results value
return 2 + 2
#+end_src

#+results:
: 4

This is explained in full at

http://orgmode.org/worg/org-contrib/babel/reference.php#header-argument-results

scroll down to the 2-by-2 table and the explanation below it.

Dan

>
> #+begin_src python :session :results value
> 2 + 2
> #+end_src
>
> #+results:
> : 4
>
> hth,
> Tom
>
>
> Thomas S. Dye, Ph.D.
>
> T. S. Dye & Colleagues, Archaeologists, Inc.
>
> Phone: (808) 529-0866 Fax: (808) 529-0884
>
> http://www.tsdye.com
>
>
>
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