refactoring-catalog

To refactor long methods and complex conditionals in Python, apply established patterns like Extract Method or Replace Conditional with Polymorphism. These patterns improve code structure while preserving behavior through small, incremental changes verified by baseline tests.

Replace Conditional with Polymorphism is a refactoring pattern that moves complex conditional logic into separate polymorphic classes. It eliminates code smells by simplifying conditionals into targeted class behaviors, improving overall software design and code maintainability.

To safely refactor a large Python codebase without altering behavior, use an incremental workflow with baseline tests. Apply one small change at a time, verify behavior after each step, and use catalog patterns like Extract Class to systematically reduce complexity.

Yes, this refactoring catalog is specifically designed for medium to large Python projects. It targets common structural issues in large codebases such as code duplication, large classes, long methods, and complex conditionals using proven software design patterns.

You should use the Extract Class refactoring pattern when a large class has multiple responsibilities causing code smells. It separates distinct behaviors into new classes, improving overall software design and maintainability while preserving the original program behavior.

The best way to eliminate code duplication in Python is to apply Martin Fowler-style refactoring patterns. By extracting duplicated logic into targeted methods or introducing parameter objects, you reduce redundancy and improve code maintainability safely.