[python] How can I check the extension of a file?

one easy way could be:

import os

if os.path.splitext(file)[1] == ".mp3":
    # do something

os.path.splitext(file) will return a tuple with two values (the filename without extension + just the extension). The second index ([1]) will therefor give you just the extension. The cool thing is, that this way you can also access the filename pretty easily, if needed!