Switch Python Version for Vim & Syntastic


Is it possible to change the python version used by syntastic for syntax checking?

As the Issue https://github.com/scrooloose/syntastic/issues/385 indicates I could use virtual-env. But is it also possible just with syntastic or vim commands?

Asked By: mjb4



Not really, but you can get the python3 incompatible warning by install
this package.

Let’s say your current Syntastic Python checker is python and you want to get
python3 incompatible warning. In command mode, you can add py3kwarn to g:syntastic_python_checkers by

:let g_syntastic_python_checkers=['python', 'py3kwarn']

and switch to python2.x only

:let g_syntastic_python_checkers=['python']
Answered By: attomos

The below is no longer necessary, and might screw up if you’re forced to work on a strictly python 2.x script.

The best option is to leave the Syntastic defaults alone, and to use conda to manage separate environments for python 3 and 2 (each with their own version-specific installs of flake8, pyflakes, etc), and to switch to the appropriate environment to edit each file. Syntastic will then call python/flake8/whatever else according to the paths set in the activated environment.

From the Syntastic repository README:

Q. The python checker complains about syntactically valid Python 3 constructs…

A. Configure the python checker to call a Python 3 interpreter rather than Python 2, e.g:

let g:syntastic_python_python_exec = '/path/to/python3'

Add that line to your .vimrc – that should fix your problem.

Answered By: naught101

I managed to convince Syntastic to handle Python 3 syntax with

pip3 install --user flake8

(to make python3 -m flake8 *.py work) and then, in vim:

let g:syntastic_python_flake8_exec = 'python3'
let g:syntastic_python_flake8_args = ['-m', 'flake8']
Answered By: Marius Gedminas

If you working under virtualenv, you can use a script that detects current python version and invokes flake8 accordingly. Put the following somewhere in your path and name is flake8.sh:

PYMAJOR=$(python --version | awk '{print $2}'| awk -F. '{print $1}')
exec "/usr/bin/python$PYMAJOR" /usr/bin/flake8 "$@"

Now in you vimrc add:

let g_syntastic_python_flake8_exe='flake8.sh'

Also make sure that both python-flake8 and python3-flake8 (on Ubuntu) are installed.

Answered By: Zaar Hai

Just to iterate on Zaar Hai’s script a bit, something like this should work and be a bit more robust.

#!/usr/bin/env bash

_python=$(command -v python)

[[ "$(uname -s)" =~ Darwin ]] && IS_OSX=true

if [[ "$IS_OSX" ]]; then
    if command -v 'greadlink' >/dev/null 2>&1; then
        greadlink -f "$_python"
        echo 'Install coreutils!' >&2
    readlink -f "$_python"
Answered By: jhrr

Only I did to fix this was to do:

  let g:syntastic_python_flake8_exec = '/path/to/python3'

To make sure flake8 is synced with Python3’s syntax.
Even when I’m in a virtualenv works.

Answered By: Luis Villavicencio

In spite of all the answers here, I still find the recommendation from the FAQ to be the best. I have added this to my .vimrc so that I can easily switch between python versions.

function Py2()
  let g:syntastic_python_python_exec = '/usr/local/bin/python2.7'

function Py3()
  let g:syntastic_python_python_exec = '/usr/local/bin/python3.6'

call Py3()   " default to Py3 because I try to use it when possible

With those functions installed, it’s easy to switch python version right within vim with :call Py2() or :call Py3() depending on what I need at the moment. No need to exit vim and activate a different virtualenv as the popular answer would have you do.

Answered By: Bruno Bronosky

Easiest solution:

Add this to you .vimrc

 let g:syntastic_python_python_exec = 'python3'
 let g:syntastic_python_checkers = ['python']

This is the straightforward solution to switch to python3.

Answered By: Raphael D.
Categories: questions Tags: , ,
Answers are sorted by their score. The answer accepted by the question owner as the best is marked with
at the top-right corner.