Dear Sacha, Ian, and Eric

Thanks very much for your replies.  Sacha's way is a clever idea and works
fine, but I think Eric's patch is the best solution in the long term.
 Please see attached test file - the patch works perfectly.  Although I did
have to study the manual carefully to work out how get it to work using the
#+call: syntax. The key is to use "inside header arguments".  Ian's
solution with shebang works when tangling but not for direct evaluation of
the source block.

Cheers

Will




On Fri, Apr 25, 2014 at 10:27 AM, Eric Schulte <schulte.eric@gmail.com>wrote:

> The attached patch should allow the specification of the python command
> through a new :python header argument.  E.g.,
>
> #+begin_src python :python /path/to/python2
>   return 1 + 2
> #+end_src
>
> If someone who actually uses python could confirm that it works as
> expected then I'll be happy to apply it.
>
>
>
> Best,
> Eric
>
> William Henney <whenney@gmail.com> writes:
>
> > Hi
> >
> > Is there an easy way to specify the python version to use for a
> particular
> > block or sub-tree?
> >
> > My use case is that I have mainly migrated to python 3, but there is
> still
> > the occasional library that has not been updated yet, so I need to fall
> > back to python 2.7 for some tasks.
> >
> > I can work around the problem by putting the python 2 code in a separate
> > org file and use
> >
> > # Local Variables:
> > # org-babel-python-command: "/path/to/python2"
> > # End:
> >
> > but keeping everything in the same file would be preferable.
> >
> > Thanks
> >
> > Will
>
> --
> Eric Schulte
> https://cs.unm.edu/~eschulte
> PGP: 0x614CA05D
>
>


-- 

  Dr William Henney, Centro de Radioastronomía y Astrofísica,
  Universidad Nacional Autónoma de México, Campus Morelia