An Introduction to the Art of Computer Programming Using Python in the Age of Generative AI

XII. Modules and Packages

Introduction to Modules

In Python, a module is a file containing Python code that defines functions, classes, and variables that can be reused in other Python programs. Modules help organize your code into manageable chunks and promote code reuse.

# Creating a module named 'my_module.py'
def greet(name):
    print(f"Hello, {name}!")
        

# Using the module in another Python script
import my_module
my_module.greet('Alice')
        

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Using Built-in Modules

Python comes with a rich set of built-in modules that you can import and use in your programs. These modules provide a wide range of functionality, from mathematical operations to file handling and system operations.

import math
result = math.sqrt(25)
print(result)
        

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Creating and Using Packages

A package is a way of organizing related modules into a single directory hierarchy. Packages allow hierarchical structuring of the module namespace using dot notation.

# Creating a package named 'my_package'
# Inside 'my_package', create a module 'my_module.py' and an empty '__init__.py' file

# Using the package in another Python script
from my_package import my_module
my_module.greet('Bob')  # Output: Hello, Bob!
        

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Installing Third-Party Packages

You can use pip, Python's package installer, to install third-party packages from the Python Package Index (PyPI). These packages provide additional functionality that can be easily integrated into your programs.

# Installing a third-party package using pip
# In your terminal or command prompt, run:
pip install requests
        

Creating Your Own Packages

You can create your own packages to share reusable code between your projects or with others. Structuring your code into packages helps maintain a clean and organized project layout.

# Creating your own package follows the same structure as shown in the 'Creating and Using Packages' section.
# Remember to include an '__init__.py' file to make Python treat the directory as a package.
        

Prompting Generative AI for Identifying and Implementing the Right Packages

Using AI can greatly improve your ability to identify and implement the right packages for your needs.

Example Prompt:

Resulting AI-generated code:

from dateutil import parser
from datetime import datetime

# Parsing a date string
date_str = "2024-05-27T10:30:00Z"
parsed_date = parser.parse(date_str)
print(f"Parsed date: {parsed_date}")

# Formatting the date
formatted_date = parsed_date.strftime("%B %d, %Y %H:%M:%S")
print(f"Formatted date: {formatted_date}")
        

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