What are modules in Python, and how do they organize code?

Python modules: Enhancing code organization and reusability

A Python module is a file containing Python code that defines variables, functions, and classes. In modules, code is organized into logical units, making it easier to reuse code across different parts of a program or across multiple programs.

Python modules serve several purposes:

• Code Organization: Modules make it easier to break down a large program into smaller, more manageable parts. You can import and use each module to handle specific functions.
• Code Reusability: Modules can be imported and used in other Python programs once they have been defined. This helps in writing DRY (Don't Repeat Yourself) code.
• Encapsulation: Modules provide a level of encapsulation, where internal details of a module can be hidden from other parts of the program, which promotes clean, maintainable code.
• Namespace: Each module defines its own namespace, preventing naming conflicts with other modules.
• To create a module, you define your Python code in a .py file. For example, if you create a file named test_module.py containing some functions, classes, or variables, you can import and use those in other parts of your program using the import statement.

Example: Python module

Code:

#test_module.py
# Define a function to check if a number is even
def is_even(x):
    return x % 2 == 0
# Define a function to check if a number is odd
def is_odd(x):
    return x % 2 != 0
# Variable to store a constant value
PI = 3.14159

You can now use the functions and variable defined in test_module.py in another Python script:

Code:

import test_module
# Using functions from the module
print("Is 7 is even? ",test_module.is_even(7))
print("Is 8 is even? ",test_module.is_even(8))
print("\nIs 3 is odd? ",test_module.is_odd(3))
print("Is 10 is odd? ",test_module.is_odd(10))
# Using the variable from the module
print("\nValue of PI:", test_module.PI)

Output:

Is 7 is even?  False
Is 8 is even?  True

Is 3 is odd?  True
Is 10 is odd?  False

Value of PI: 3.14159

In the above example , the code in main.py imports the test_module module and uses the functions is_even() and is_odd() as well as the constant PI defined in the module.