In order to auto format your python code according to the guidelines defined by PEP8, you can use some sane default for editing python files and flake8 to check and fix possible errors in your scripts.

Default indentation rules for python files

The default indentation rules do not comply with PEP8. In order to change them for python files, create a new file in ~/.vim/ftplugin/python.vim and place the following content in this file:

setlocal tabstop=4
setlocal softtabstop=4
setlocal shiftwidth=4
setlocal smarttab
setlocal expandtab
setlocal shiftround
setlocal autoindent

PEP8 recommends that code should have a maximum line length of 79 characters. You can enforce this by adding the following line to the file:

setlocal textwidth=79

However, it can be a good idea to have longer lines, I prefer to not have a hard wrap at 79. You can therefore opt to show a marker that helps you to avoid the character line limit by setting:

setlocal colorcolumn=80
Install flake8

flake8 is a python module that you can install using your favourite package manager, e.g. using pip:

sudo pip install flake
Install vim-pathogen and vim-flake8

vim-pathogen is a vim script that helps with managing the runtimepath to simplify the vim plugin management. You can install it by running the following command:

mkdir -p ~/.vim/autoload ~/.vim/bundle && \
curl -LSso ~/.vim/autoload/pathogen.vim https://tpo.pe/pathogen.vim

then add the following to your .vimrc

execute pathogen#infect()

Afterwards, install vim-flake8:

cd ~/.vim/bundle
git clone https://github.com/nvie/vim-flake8

This is everything you need to do. Afterwards, you can open vim on a python file and press < F7 > to start flake and obtain information on your formatting.