Chapter 25: IO and File Handling
Programs need to interact with the outside world. They accept user input, display results, save data to files, load configurations, and process structured data. Input/output operations are the foundation of every useful program—without I/O, your code lives in isolation.
You'll learn how programs interact with users through the console, persist data to files for long-term storage, organize file systems using cross-platform paths, and work with structured data formats like CSV and JSON. By the end, you'll build a complete Note-Taking CLI application that integrates all these concepts. This chapter applies the AI-Native Learning methodology you've practiced since Chapter 1: you describe what you want your code to do, explore concepts with your AI companion, validate your understanding through interactive programs, and learn from errors by asking "why?"
This is the same pattern you'll use throughout your professional career. Your AI tool isn't a crutch—it's a partner in learning.
🎯 Before You Begin
What You'll Learn
By the end of this chapter, you will be able to:
- Gather and validate console input with proper error handling and formatted output
- Read and write files safely using context managers and exception handling
- Work with file paths across Windows, Mac, and Linux using pathlib
- Load and save structured data in CSV and JSON formats with correct encoding
- Build a complete CLI application integrating all I/O concepts (Capstone)