Book Image

Python Object-Oriented Programming - Fourth Edition

By : Steven F. Lott, Dusty Phillips
2 (2)
Book Image

Python Object-Oriented Programming - Fourth Edition

2 (2)
By: Steven F. Lott, Dusty Phillips

Overview of this book

Object-oriented programming (OOP) is a popular design paradigm in which data and behaviors are encapsulated in such a way that they can be manipulated together. Python Object-Oriented Programming, Fourth Edition dives deep into the various aspects of OOP, Python as an OOP language, common and advanced design patterns, and hands-on data manipulation and testing of more complex OOP systems. These concepts are consolidated by open-ended exercises, as well as a real-world case study at the end of every chapter, newly written for this edition. All example code is now compatible with Python 3.9+ syntax and has been updated with type hints for ease of learning. Steven and Dusty provide a comprehensive, illustrative tour of important OOP concepts, such as inheritance, composition, and polymorphism, and explain how they work together with Python’s classes and data structures to facilitate good design. In addition, the book also features an in-depth look at Python’s exception handling and how functional programming intersects with OOP. Two very powerful automated testing systems, unittest and pytest, are introduced. The final chapter provides a detailed discussion of Python's concurrent programming ecosystem. By the end of the book, you will have a thorough understanding of how to think about and apply object-oriented principles using Python syntax and be able to confidently create robust and reliable programs.
Table of Contents (17 chapters)
15
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16
Index

Operator overloading

Python's operators, +, /, -, *, and so on, are implemented by special methods on classes. We can apply Python operators more widely than the built-in numbers and collection types. Doing this can be called "overloading" the operators: letting them work with more than the built-in types.

Looking back at the The collections.abc module section, earlier in this chapter, we dropped a hint about how Python connects some built-in features with our classes. When we look at the collections.abc.Collection class, it is the abstract base class for all Sized, Iterable, Containers; it requires three methods that enable two built-in functions and one built-in operator:

  • The __len__() method is used by the built-in len() function.
  • The __iter__() method is used by the built-in iter() function, which means it's used by the for statement.
  • The __contains__() method is used by the built-in in operator. This operator is implemented by methods...