As statisticians and data scientists, we strive to build systems that produce valuable insights. To accomplish this, we normally use two tools—mathematics and computers. This book was developed for people who are comfortable with the mathematics side but feel that their R programming skills need improvement.

Normally, when people with mathematical backgrounds are introduced to programming, they are introduced through a functional approach, which means that they think in terms of algorithms with inputs and outputs, which are implemented as functions. This way of working is intuitive if you come from a mathematical background and are not dealing with high level abstractions, and it is the way we have been working throughout the book up to this point.

This chapter will show a different way of programming called object-oriented...