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Week 3: Input/Output & Exceptions¶

Welcome to Week 3 - the final week! This week you'll learn how to work with files and handle errors gracefully.

Overview¶

In this final week, you'll learn essential skills for building robust applications that interact with the file system and handle errors properly. By the end of this week, you'll understand:

  • Reading from and writing to files
  • Different file formats and modes
  • Exception handling and debugging
  • Using assertions for code validation
  • Error checking best practices

Lessons¶

Work through these lessons in order:

  1. Input & Output - Reading and writing files
  2. Exceptions & Assertions - Error handling and debugging
  3. Additional Links - Resources for continued learning

Homework Assignment¶

Text Reader & Writer - Create an application that reads, processes, and writes text files with proper error handling.

Check the HW folder for detailed requirements and starter code.

Learning Objectives¶

By the end of Week 3, you should be able to:

  • Open, read, and write files in various modes
  • Handle different file formats (text, CSV, JSON)
  • Use context managers (with statement) for resource management
  • Catch and handle exceptions appropriately
  • Raise custom exceptions
  • Use assertions for debugging
  • Write defensive code that handles errors gracefully

Estimated Time¶

  • Lessons: 1.5-2 hours
  • Homework: 3-4 hours
  • Total: 4.5-6 hours

Key Concepts¶

File I/O¶

Working with files is essential for most applications: - Opening files with open() - Reading methods: read(), readline(), readlines() - Writing methods: write(), writelines() - File modes: 'r', 'w', 'a', 'r+', etc. - Context managers with with statement

Exception Handling¶

Write robust code that handles errors: - Try/except blocks - Multiple exception types - Finally clauses - Raising exceptions - Custom exception classes - Assertions for debugging

Tips for Success¶

  1. Always use context managers - Use with when working with files
  2. Handle specific exceptions - Don't use bare except: clauses
  3. Provide helpful error messages - Tell users what went wrong
  4. Clean up resources - Close files, connections, etc.
  5. Test error conditions - Make sure your error handling works

Beyond the Bootcamp¶

Congratulations on reaching the final week! After completing this week, you'll have a solid foundation in Python. Here's what to do next:

Continue Learning¶

  • Explore the Additional Links lesson
  • Check out advanced Python topics (OOP, decorators, context managers)
  • Learn popular libraries (requests, pandas, numpy)
  • Explore web frameworks (Flask, Django)

Build Projects¶

The best way to learn is by building: - Automate repetitive tasks - Create web scrapers - Build data analysis tools - Develop web applications - Contribute to open source

Join the Community¶

  • Participate in coding challenges (LeetCode, HackerRank)
  • Attend Python meetups
  • Join online communities (Reddit r/learnpython, Python Discord)
  • Follow Python developers on social media

Resources¶

Final Notes¶

You've covered a lot of ground in these three weeks! Remember: - Programming is a skill that improves with practice - Everyone struggles sometimes - that's part of learning - The Python community is welcoming and helpful - Keep building, keep learning, keep coding!

Good luck with your final homework assignment and your Python journey!