Defining a new S4 class

You have seen that the S3 class does not have any formal definition, and as a result, there is a greater chance of making naïve mistakes. The S4 class is more rigorous, and it has a formal definition and a uniform way to create objects. In this recipe, you will define a new S4 class robustSummary.

Getting ready

Suppose you have a numeric vector x representing the number of hours spent on social media in a week. You want to define a new S4 class that will display the robust descriptive statistics. The name of the new class will be robustSummary, and the individual items of this class will be as follows:

• Median
• MAD
• First quartile
• Third quartile

Here is the original vector with 50 numeric values:

    x <- c(13, 21, 19, 18, 21, 16, 21, 24, 17, 18, 12, 18, 29, 17, 18, 
    11, 13, 20, 25, 18, 15, 19, 21, 21, 7, 12, 23, 31, 16, 19, 23, 15, 
    25, 19, 15, 25, 25, 16, 29, 15, 26, 29, 23, 24, 20, 19, 14, 27, 22, 
    26)

How to do it…

Take a look at the following steps:

1. To define...