R in a Nutshell, 2nd Edition

Chapter 7. R Objects

All objects in R are built on top of a basic set of built-in objects. The type of an object defines how it is stored in R. Objects in R are also members of a class. Classes define what information objects contain, and how those objects may be used.

R provides some mechanisms for object-oriented programming (which doesn’t just mean “programming with objects”). This chapter focuses on built-in objects and how to use them and not on the object-oriented programming system. We’ll discuss object-oriented programming features like class definitions, inheritance, and methods in Chapter 10.