Package structure and usage in Python

Introduction

Packages help organize your Python code into folders so it is easier to find and reuse.

You want to group related Python files together in one folder.

You want to reuse code across different projects by importing it easily.

You want to avoid name conflicts by separating code into different packages.

You want to share your code with others as a package.

You want to keep your project organized as it grows bigger.

Syntax

Python

package_name/
    __init__.py
    module1.py
    module2.py

# To use a module from the package:
from package_name import module1
module1.some_function()

The __init__.py file tells Python this folder is a package.

You import modules from the package using from package_name import module.

Examples

This example shows a package named my_package with one module greetings.py. We call the say_hello function from it.

Python

my_package/
    __init__.py
    greetings.py

# greetings.py content:
def say_hello():
    print('Hello!')

# Using the package:
from my_package import greetings
greetings.say_hello()

This example shows a package utils with two modules. We import both and use their functions.

Python

utils/
    __init__.py
    math_tools.py
    string_tools.py

# math_tools.py content:
def add(a, b):
    return a + b

# string_tools.py content:
def shout(text):
    return text.upper() + '!'

# Using the package:
from utils import math_tools, string_tools
print(math_tools.add(3, 4))
print(string_tools.shout('hi'))

Sample Program

This program shows how to create a package my_package with a module greetings. Then it imports and uses the say_hello function.

Python

# Folder structure:
# my_package/
#     __init__.py
#     greetings.py

# greetings.py content:
def say_hello():
    print('Hello from the package!')

# main.py content:
from my_package import greetings

greetings.say_hello()

Important Notes

Every folder that should be a package needs an __init__.py file, even if it is empty.

You can import specific functions or classes from modules inside packages for cleaner code.

Packages help keep your project tidy and make code sharing easier.

Summary

Packages are folders with Python files and an __init__.py file.

Use packages to organize and reuse your code easily.

Import modules from packages using from package_name import module.