Inheritance reuses code

Case Study: Building Software in Python

Mark Pedigo

Principal Data Scientist

Roadmap

Roadmap showcasing what parts of the project we've finished and which we'll be starting.

Review of what you've built so far

BasicCalculator()
- Basic arithmetic operations
FinancialCalculator
- Inherits from BasicCalculator
- Method for financial calculation

class BasicCalculator:
  def multiply(self, x, y):
      result = x * y
      return result
  ...

# Child of BasicCalculator
class FinancialCalculator(BasicCalculator):
    def monthly_interest(self, annual_interest_rate):
        return self.divide(annual_interest_rate, 12)
    ...

Inheritance Reuses Code

Inheritance for code reuse
- Reuse code from a parent class
Class hierarchy
- Inherit from child to "grandchild" classes
Flexible structure
- Develop a flexible and organized class hierarchy

Other types of inheritance

Multilevel inheritance
- Class inherits from a subclass of another class
- Used in case study - BasicCalculator to FinancialCalculator to MortgageCalculator
Hierarchical inheritance
- Multiple classes inherit from the same parent class
Multiple inheritance
- Class inherits from two or more unrelated classes

Using super()

Access parent methods and properties
- Use super() without directly naming the parent class
Handles complex inheritance
- Prevents code duplication and errors in class hierarchies

class Animal:
    def __init__(self, name):
        self.name = name

class Dog(Animal):
    def __init__(self, name):
          # super calls __init__ 
          # method from parent class
          super().__init__(name)

Let's practice!

Case Study: Building Software in Python