The __file__ Attribute in Python

In Python, modules and packages typically have a __file__ attribute. This attribute is a string containing the absolute path to the file from which the module was loaded.

• For a regular module, it points to the .py file.
• For a package, it points to the package’s __init__.py.
• For compiled extension modules, it may point to a shared object file (e.g., .so, .pyd).

Examples

In [1]: import collections

In [2]: collections.__file__
Out[2]: '/Users/diegoallen/.asdf/installs/python/3.11.1/lib/python3.11/collections/__init__.py'

In [3]: import inspect

In [4]: inspect.__file__
Out[4]: '/Users/diegoallen/.asdf/installs/python/3.11.1/lib/python3.11/inspect.py'

In [5]: import math

In [6]: math.__file__
Out[6]: '/Users/diegoallen/.asdf/installs/python/3.11.1/lib/python3.11/lib-dynload/math.cpython-311-darwin.so'

Why It’s Useful

The __file__ attribute is helpful when you need to:

• Quickly locate the active virtual environment.
• Inspect the source code of standard library modules.
• Review the implementation of third-party dependencies.