Modern R Programming Cookbook

How to do it…

Let's take a look at the following steps:

1. The new generic function can be created as follows:

        robSum <- function(obj) {          UseMethod("robSum")        }

2. A default method for robSum() is created as follows:

        robSum.default <- function(obj){          cat("This is a generic function for the object class           'robustSummary'")        }

3. A new method for the robSum() generic function for the object class can be created as follows:

        # robustSummary        robSum.robustSummary <- function(obj){          cat("Median ", median(obj), "\n")          cat("Median Absolute Deviation (MAD)", mad(obj), "\n")          cat("First Quartile (Q1)", as.numeric(quantile(obj, probs =           0.25)), "\n")          cat("Third Quartile (Q3)", as.numeric(quantile(obj, probs =            0.75)))        }