Namespaces and Scope

Modules and Packages

Python’s modularity is a key strength. It allows for code reusability and organization.

Modules: A single Python file (.py) containing functions, classes, and variables. Think of it as a toolbox with specific tools.

# my_module.py
def my_function(x):
  return x * 2

my_variable = 10

To use my_function and my_variable, you import the module:

import my_module

result = my_module.my_function(5)  # result will be 10
print(my_module.my_variable)       # prints 10

You can also import specific elements:

from my_module import my_function, my_variable

result = my_function(5) # result will be 10
print(my_variable)      # prints 10

Or rename things during import:

from my_module import my_function as func, my_variable as var

result = func(5) # result will be 10
print(var)      # prints 10

Packages: A collection of modules organized in a directory hierarchy. The directory must contain an __init__.py file (can be empty), which signals to Python that it’s a package. Packages help structure larger projects.

mypackage/
├── __init__.py
├── module1.py
└── module2.py

Importing from a package:

import mypackage.module1

mypackage.module1.some_function()

from mypackage.module2 import some_other_function
some_other_function()

The __init__.py File (Explains the purpose and functionality of __init__.py in more detail.)

Package Management with Pip (How to install and manage external packages using pip)