Python modules are powerful tools for organizing and reusing code. They allow you to group related functions and variables into separate files, making your programs more manageable and easier to maintain.

By creating custom modules, you can import and use your own functions across different scripts. This modular approach enhances code organization, promotes reusability, and helps prevent naming conflicts in larger projects.

Python Modules

Python module creation

• Create a Python file with a .py extension to define a module
• Modules organize related code into separate files for reusability and maintainability (code reusability)
• Define functions within the module file, each with a clear purpose and descriptive name
• Functions can accept parameters and return values as needed
• Example module file math_utils.py:

  def add_numbers(a, b):
      return a + b
  
  def multiply_numbers(a, b):
      return a  b
  

Custom module usage

• Import the custom module into your Python program using the import statement
• Bring the module into your current script by specifying its name
• Call the functions defined in the module using the syntax module_name.function_name()
• Example of importing and using functions from math_utils.py:

  import math_utils
  
  result1 = math_utils.add_numbers(5, 3)
  result2 = math_utils.multiply_numbers(4, 7)
  
  print(result1)  # Output: 8
  print(result2)  # Output: 28
  

Module filenames and imports

• Use the module's filename (without .py) in the import statement
• Python searches for the specified file in the current directory and sys.path directories
• The import statement connects the current script with the imported module
• Import multiple modules by separating them with commas (import module1, module2, module3)
• Place import statements at the beginning of your script for clarity and organization
• Provide the appropriate path in the import statement for modules in different directories
  • Example: import package.subpackage.module

Module concepts and organization

• Modules create separate namespaces, preventing naming conflicts between different parts of a program
• Modular programming allows for better organization and maintenance of large codebases
• Python's standard library provides a wide range of pre-built modules for common tasks
• In package directories, an __init__.py file indicates that the directory should be treated as a package