Inheritance in R

Inheritance is a fundamental concept in object-oriented programming (OOP) that helps you to reuse code and establish a hierarchical relationship between the classes. In R, inheritance is achieved using the extends function.

Here's an example of how to use inheritance in R:

# Define parent class
setClass("Animal",
         slots = c(name = "character", age = "numeric"))
# Define child classes that inherit from Animal

setClass("Mammal",

         contains = "Animal",

         slots = c(fur_color = "character"))
setClass("Bird",

         contains = "Animal",

         slots = c(wing_span = "numeric"))
# Create objects of child classes

dog <- new("Mammal", name = "Buddy", age = 5, fur_color = "brown")

penguin <- new("Bird", name = "Opus", age = 3, wing_span = 30)
# Access slots of parent class

dog@name # "Buddy"

penguin@age # 3 (age is a common slot in parent class Animal)
# Access slots of child classes

dog@fur_color # "brown"

penguin@wing_span # 30

In the above code, we defined a parent class Animal with two slots "name" and "age". We then defined two child classes Mammal and Bird that inherit from the parent class Animal and have additional slots "fur_color" and "wing_span", respectively. We created two objects dog and penguin of the child classes and accessed their slots using the @ symbol.

By using inheritance, we avoided duplicating the slots "name" and "age" in the child classes and reused them from the parent class. This makes the code easier to maintain and extend.