L5: Advanced Functions

Overview

This lecture explores advanced function concepts in Python, building on the fundamentals from L4. You will learn about programming paradigms (procedural, functional, object-oriented), first-class functions, lambda expressions, closures, callables, decorators, and partial functions. These concepts are essential for writing clean, reusable, and composable Python code and form the foundation for object-oriented programming in later lectures.

Learning Objectives

By the end of this lecture, you will be able to:

• Distinguish imperative, functional, and object-oriented programming paradigms.

• Use functions as first-class objects: assign, pass, and return them.

• Write anonymous functions with lambda and understand their limitations.

• Explain closures and how inner functions capture enclosing state.

• Make objects callable with the __call__ dunder method.

• Write and apply decorators to extend function behavior.

• Stack multiple decorators and preserve function metadata with functools.wraps.

• Create partial functions using functools.partial.

• Use built-in higher-order functions: map, filter, and sorted with key.

Next Steps

• In the next lecture, we will cover Object-Oriented Programming I:

  • Classes and objects

  • Attributes and methods

  • Constructors and __init__

  • Encapsulation and properties

  • Dunder methods

• Review and experiment with all code snippets and exercises from today’s lecture.

• Practice writing decorators and closures.

• Read Real Python: Python Classes.