Pyflakes

The pyflakes checker tries very hard to find errors in Python source files. (It does not care about style.)

Pycodestyle

So for style I use pycodestyle checker (formerly known as pep8). It checks your code against the conventions of PEP 8.

Personally I do like to relax the PEP 8 maximum line length of 79 characters. In general I like to try to keep line length below 80 characters. But if incidentally is somewhat more, It doesn’t bother me. So I generally use pycodestyle with the argument --max-line-length=100.

Syntastic

This is a plugin for the vim editor that lets you run checker programs on your code when you save it. Currently I use this to run python, pycodestyle and pyflakes.

Since I save regularly, I get fast feedback on errors and potential issues. This has probably been the most helpful in teaching me good coding habits and solving problems when they occur.

Pydocstyle

Documentation is almost as important as your code; it is probably the first thing that a user of a module will read.

So I’m in the process of checking all my Python code with pydocstyle.

Since some of the default checks that it runs are contradictory, I’ve created a .pydocstylerc file in my home directory with the following contents:

[pydocstyle]
ignore = D203,D212,D406,D407,D408,D409,D413

This ignores the following violations that I don’t agree with:

D203

1 blank line required before class docstring. (Contradicts D211).

D212

Multi-line docstring summary should start at the first line. (Contradicts D213).

D406

Section name should end with a newline. (Complains about “Returns:” instead of “Returns”).

D407,D408,D409

All about underlining section names, which I don’t do.

D413

Missing blank line after last section.

Yapf

While yapf is a excellent reformatting tool, it has some limitations on Python 3. It crashes hard on unicode identifiers, because of its internal usage of lib2to3.

It works fine when your code does not contain unicode identifiers, though. I use it with its standard settings.