10. Object-Oriented Programming

Objectives

• Create custom classes and objects of those classes.
• Understand the benefits of crafting valuable classes.
• Control access to attributes.
• Appreciate the value of object orientation.
• Use Python special methods __repr__, __str__ and __format__ to get an object’s string representations.

Objectives (cont.)

• Use Python special methods to overload (redefine) operators to use them with objects of new classes.
• Inherit methods, properties and attributes from existing classes into new classes, then customize those classes.
• Understand the inheritance notions of base classes (superclasses) and derived classes (subclasses).

Objectives (cont.)

• Understand duck typing and polymorphism that enable “programming in the general.”
• Understand class object from which all classes inherit fundamental capabilities.
• Compare composition and inheritance.
• Build test cases into docstrings and run these tests with doctest,
• Understand namespaces and how they affect scope.

Outline

• 10.1 Introduction
• 10.2 Custom Class Account
  • 10.2.1 Test-Driving Class Account
  • 10.2.2 Account Class Definition
  • 10.2.3 Composition: Object References as Members of Classes
• 10.3 Controlling Access to Attributes
• 10.4 Properties for Data Access
  • 10.4.1 Test-Driving Class Time
  • 10.4.2 Class Time Definition
  • 10.4.3 Class Time Definition Design Notes
• 10.5 Simulating “Private” Attributes
• 10.6 Case Study: Card Shuffling and Dealing Simulation
  • 10.6.1 Test-Driving Classes Card and DeckOfCards
  • 10.6.2 Class Card—Introducing Class Attributes
  • 10.6.3 Class DeckOfCards
  • 10.6.4 Displaying Card Images with Matplotlib
• 10.7 Inheritance: Base Classes and Subclasses
• 10.8 Building an Inheritance Hierarchy; Introducing Polymorphism
  • 10.8.1 Base Class CommissionEmployee
  • 10.8.2 Subclass SalariedCommissionEmployee
  • 10.8.3 Processing Commission-Employees and Salaried-CommissionEmployees Polymorphically
  • 10.8.4 A Note About Object-Based and Object-Oriented Programming
• 10.9 Duck Typing and Polymorphism
• 10.10 Operator Overloading
  • 10.10.1 Test-Driving Class Complex
  • 10.10.2 Class Complex Definition
• 10.11 Exception Class Hierarchy and Custom Exceptions
• 10.12 Named Tuples
• 10.13 A Brief Intro to Python 3.7’s New Data Classes
  • 10.13.1 Creating a Card Data Class
  • 10.13.2 Using the Card Data Class
  • 10.13.3 Data Class Advantages over Named Tuples
  • 10.13.4 Data Class Advantages over Traditional Classes
• 10.14 Unit Testing with Docstrings and doctest
• 10.15 Namespaces and Scopes
• 10.16 Intro to Data Science: Time Series and Simple Linear Regression
• 10.17 Wrap-Up

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