Difference between __file__ and sys.argv[0]

Question

Is there any difference between:

__file__

and

sys.argv[0]

Because both seem to be doing the same thing: they hold the name of the script.

If there is no difference, then why is it that __file__ is used in almost all someplaces whereas I have never seen sys.argv[0] being used.

Answer 1

__file__ is the name of the current file, which may be different from the main script if you are inside a module or if you start a script using execfile() rather than by invoking python scriptname.py. __file__ is generally your safer bet.

Answer 2

It's only the same if you are in the "main" script of your python programm. If you import other files, __file__ will contain the path to that file, but sys.argv will still hold the same values.