Difference between a module and a package

Modules

A module is a single Python file that can be imported. Using a module looks like this:

module.py

def hi():
    print("Hello world!")

my_script.py

import module
module.hi()

in an interpreter

>>> from module import hi
>>> hi()
# Hello world!

Packages

A package is made up of multiple Python files (or modules), and can even include libraries written in C or C++. Instead of being a single file, it is an entire folder structure which might look like this:

Folder package

• __init__.py
• dog.py
• hi.py

__init__.py

from package.dog import woof
from package.hi import hi

dog.py

def woof():
    print("WOOF!!!")

hi.py

def hi():
    print("Hello world!")

All Python packages must contain an __init__.py file. When you import a package in your script (import package), the __init__.py script will be run, giving you access to the all of the functions in the package. In this case, it allows you to use the package.hi and package.woof functions.

Putting package in .zip

It is possible to put a Python package in a ZIP file, and use it that way if you add these lines to the beginning of your script:

import sys
sys.path.append("package.zip")