Migrating from Python 2.7 to Python 3

Introduction

• Getting started with migrating Python

1. Python 2 and Python 3

• The challenges of migrating from Python 2 to 3
• Historical overview
• The official how to guide
• The obvious differences in Python 3

2. Feature Comparisons

• The language syntax changes
• Syntax changes that have to wait
• Changes to the internal types
• Changes to Python built-in functions
• Changes to the Python standard library

3. Conversion Strategies: Manual or Automated

• Navigation among the strategies
• Readying the toolbox
• Manual rewrite
• Automated migration via 2to3
• Final cleanup

4. Using Six

• Overview of the features of six
• Syntax wrapping with six
• Handling class definitions with six
• Using six to manage built-in functions
• Using six with standard library changes

5. Using Pytest for Unit Testing

• Overview of the goals of unit testing
• Capturing Python 2 features as tests
• Mocking and monkey patching
• Design for testability
• Bugs: Fix or preserve?

6. Using 2to3 to Automate Conversion

• Overview of the features of 2to3
• Syntax and class definitions
• Built-ins and library migrations
• Test automation with tox
• Type checking with mypy

Conclusion

• Final thoughts
• Continuing on with Python 3