How get python major version without any additional package?

Question

I need a function that return major version of "current" python interpreter. Possible choices are 2 or 3. How can I get it? Please, help me with this func.

score 4 · Accepted Answer · edited Apr 13 '17 at 12:52

4

Use shell-command-to-string and split-string:

(second (split-string (shell-command-to-string "python --version")))
==> "2.7.12+"

If you insist on a major version number, you can use string-to-number:

(string-to-number (first (split-string (second (split-string (shell-command-to-string "python --version"))) "\\.")))
==> 2

or (see string-match and match-string)

(let ((pv (shell-command-to-string "python --version")))
  (if (string-match "Python \\([0-9]+\\)\\." pv)
      (string-to-number (match-string 1 pv))
      (error "Unexpected `python --version` output [%s]" pv)))
==> 2

Note that in all cases you will get the version of whatever python executable found in the exec-path. IOW, normally this would be the system-wide /usr/bin/python, unless you started Emacs in a virtual environment or set it inside Emacs.

edited Apr 13 '17 at 12:52

Community

1

answered Mar 10 '17 at 04:16

sds

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This would report only the systems default, not the version at place inside a virtualenv maybe. – Andreas Röhler Mar 13 '17 at 13:42
@AndreasRöhler: not necessarily, please see note and the end. – sds Mar 13 '17 at 13:54
There might exist links from python to python2 or 3. While inside Emacs source, by shebang or other customization, the default might be not selected. – Andreas Röhler Mar 13 '17 at 15:30

How get python major version without any additional package?

1 Answers1