R6 classes in R Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an R6 class in R?

An R6 class is a way to create objects with methods and fields in R, allowing for object-oriented programming with encapsulation and inheritance.

beginner

How do you create a new R6 class?

Use the <code>R6Class()</code> function, specifying the class name, public methods, and fields inside it.

intermediate

What is the difference between public and private members in R6 classes?

Public members can be accessed from outside the object, while private members can only be accessed inside the class methods.

beginner

How do you create an object from an R6 class?

Call the <code>$new()</code> method on the R6 class to create a new object instance.

intermediate

Can R6 classes inherit from other R6 classes?

Yes, R6 classes support inheritance by specifying the inherit argument in R6Class().

Which function is used to define an R6 class?

A R6Class()

B class()

C new()

D createClass()

The R6Class() function is used to define R6 classes in R.

How do you access a public method named greet from an R6 object obj?

A obj.greet()

B obj$greet()

C obj->greet()

D obj[greet]

In R6, methods and fields are accessed using the $ operator, so obj$greet() calls the method.

What does the $new() method do in R6?

A Changes class name

B Deletes an object

C Lists all methods

D Creates a new object instance

The $new() method creates a new instance of the R6 class.

Which of these is true about private members in R6 classes?

A They can only be accessed inside class methods

B They are accessible from outside the object

C They are the same as public members

D They do not exist in R6

Private members are hidden from outside and only accessible inside the class methods.

How do you specify inheritance in an R6 class?

A Inheritance is not supported

B Using extends keyword

C Using the inherit argument in R6Class()

D Using super() function

Inheritance is specified by the inherit argument inside R6Class().

Explain how to create an R6 class with a public field and a method that prints a message.

Think about how you define fields and methods inside the public list.

Describe the difference between public and private members in R6 classes and why encapsulation is useful.

Consider how controlling access helps protect data inside objects.