Module, Package

[Steven D'Aprano]

On Mon, 07 May 2018 09:53:45 -0700, Sharan Basappa wrote:

> I am a bit confused between module and package in Python. Does a module
> contain package or vice versa? When we import something in Python, do we
> import a module or a package?

The term "module" in Python has multiple meanings:

- a particular kind of object, types.ModuleType

- a single importable .py, .pyc etc file

A package is a logical collection of importable .py etc files, usually 
collected inside a single directory. When you import a module of a 
package, that gives you a module object.

Normally we would say that packages contain modules. For example, if you 
have this file structure:


library/
+-- __init__.py   # special file which defines a package
+-- widgets.py
+-- stuff/
    +-- __init__.py
    +-- things.py


then we have a package "library", which in turn contains a submodule 
"library.widgets", and a subpackage "library.stuff", which in turn 
contains a submodule "library.stuff.things".

Each of these lines imports a module object:

import library
import library.stuff
import library.stuff.things
import library.widgets

from library import widgets
from library.stuff import things


Effectively, "packages" relates to how you arrange the files on disk; 
"modules" relates to what happens when you import them.


-- 
Steve