Using python2.7 with Emacs 24.3 and python-mode.el

Question

I'm new to Emacs and I'm trying to set up my python environment. So far I've learned that using "python-mode.el" in a python buffer C-c C-c loads the contents of the current buffer into an interactive python shell, apparently using what which python yields. In my case that is python 3.3.3. But since I need to get a python 2.7 shell, I'm trying to get Emacs to spawn such a shell on C-c C-c. Unfortunatly I can't figure out, how to do this. Setting py-shell-name to what which python2.7 yields (i.e. /usr/bin/python2.7) does not work. How can get Emacs to do this, or how can I trace back what Emacs executes when I hit C-c C-c?

Answer 1

python-mode.el, execute a python buffer using python2:

M-x py-execute-buffer-python2

or put this in .emacs file:

(custom-set-variables
    '(py-force-py-shell-name-p t)
    '(py-shell-name "python2"))

python-mode.el checks py-force-py-shell-name-p variable when executing py-execute-buffer(bound to C-c C-c key), and if this variable is set to true("t"), then use python interpreter name saved in py-shell-name.

Alternatively, this customization can be done in M-x customize, Programming>Languages>Python Mode, search there for "Py Force Py Shell" and "Py Shell Name" lines. It will add this customization code to your .emacs file.

Emacs help(describe function):

C-h f py-execute-buffer TAB

You can send selected region in a python buffer to any interpreter:

C-u 3 M-x py-execute-region

Emacs will prompt every time for a python interpreter name you want to use. The prefix numerical argument may be any number except 1 or 4, otherwise it will use a default interpreter without prompt.

To execute a buffer in different python interpreters you can select whole buffer by C-x h and then use this prefixed command.

Answer 2

I don't use python, but from the source to python-mode, I think you should look into customizing the variable python-python-command - It seems to default to the first path command matching "python"; perhaps you can supply it with a custom path?