Package structure and usage in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Python package?

A Python package is a folder that contains a special file called __init__.py and other Python files or subfolders. It helps organize code into groups so it is easier to find and use.

beginner

What is the purpose of the __init__.py file in a package?

The __init__.py file tells Python that the folder should be treated as a package. It can be empty or contain code that runs when the package is imported.

beginner

How do you import a module from a package?

Use the dot notation: <code>import package_name.module_name</code> or <code>from package_name import module_name</code>. This lets you use the code inside that module.

intermediate

What is a subpackage in Python?

A subpackage is a package inside another package. It is a folder with its own __init__.py file inside the main package folder.

beginner

Why is organizing code into packages helpful?

It keeps code neat and easy to find, helps avoid name conflicts, and makes it easier to share and reuse code in different projects.

What file must be present in a folder for Python to recognize it as a package?

A setup.py

B main.py

C __init__.py

D package.py

The __init__.py file marks a folder as a Python package.

How do you import the module tools from the package utils?

A import tools.utils

B import utils-tools

C from tools import utils

D import utils.tools

Use import utils.tools to import the tools module inside the utils package.

What is a subpackage?

A A module inside a package

B A package inside another package

C A file named <code>subpackage.py</code>

D A package without <code>__init__.py</code>

A subpackage is a package folder inside another package folder.

Which statement is true about __init__.py?

A It can contain code that runs when the package is imported

B It must always be empty

C It is only needed for Python 3.12+

D It is used to run scripts

__init__.py can be empty or contain initialization code for the package.

Why use packages in Python?

A To organize code and avoid name conflicts

B To make code run faster

C To write code without indentation

D To create executable files

Packages help organize code and prevent name conflicts by grouping related modules.

Explain what a Python package is and how it is structured.

Think about folders and special files that group code.

Describe how to import a module from a package and why this is useful.

Consider how you tell Python where to find the code you want.