Python code that traverses one or more directories, removing any orphaned .pyc's.

cleanup.py

"""Traverses the directory tree deleting any .pyc's who do not have a source .py.
Helpful when switching between revisions with source control."""
from os.path import join
from os import walk, unlink
import re
import sys

PYTHON_RE = re.compile(R'^(.*\.py)(c)?$')

global count
count = 0

directories = sys.argv[1:] if len(sys.argv) > 1 else ['.']
for directory in directories:
    for (dirpath, dirnames, filenames) in walk(directory):
        source_set = set()
        pyc_set = set()
        for filename in filenames:
            match = PYTHON_RE.match(filename)
            if match is not None:
                (source_set if match.group(2) is None else pyc_set).add(match.group(1))
        to_remove = (pyc_set - source_set)
        for extra in to_remove:
            unlink(join(dirpath, extra + 'c'))
            count += 1

if count > 0:
    print 'Removed \033[91m%d\033[0m file%s' % (count, 's' if count > 1 else '')

What if you have lots of unrelated directories. Couldn't this be improved by only walking PYTHONPATH?

The code as is traverses whatever directories you pass as arguments. It might make sense to filter against paths that are in the PYTHONPATH, but I'd not want to traverse the entire PYTHONPATH as usually that isn't all version controlled.