Module vs. Package?

Question

Whenever I do from 'x' import 'y' I was wondering which one is considered the 'module' and which is the 'package', and why it isn't the other way around?

• Michael Butscher: Packages are containers for modules and other subpackages. In your example x is the package and y the module, similar to "from the shopping bag take the apple", not the other way around.

Answer 1

x may be a package or a module and y is something inside that module/package.

A module is a .py file, a package is a folder with an __init__.py file. When you import a package as a module, the contents of __init__.py module are imported.

• wim: Packages don't necessarily have an __init__.py file, and modules aren't necessarily .py files.
• geckos: You don't need __init__.py file in Python 3 and module maybe anything since import hooks were invented but these are exception for the above conventions. 99% of the time the above applies.
• SpaceCadet: Thank you for the explanations! This helps!
• Martin Thoma: @geckos Could you please elaborate on those exceptions? Can you add a link for the import hooks? The official python docs state "The init.py files are required to make Python treat directories containing the file as packages.". Are the docs outdated?
• geckos: docs.python.org/3/reference/import.html#import-hooks @MartinThoma

Answer 2

A Python module is simply a Python source file, which can expose classes, functions and global variables.

When imported from another Python source file, the file name is treated as a namespace.

A Python package is simply a directory of Python module(s).

For example, imagine the following directory tree in /usr/lib/python/site-packages:

mypackage/__init__.py <-- this is what tells Python to treat this directory as a package
mypackage/mymodule.py

So then you would do:

import mypackage.mymodule

or

from mypackage.mymodule import myclass