Methods belong to the object . You call them using the $ operator (e.g., my_object$do_something() ). The Core Systems 1. S3: The Pragmatic Standard

S4 is a more formal version of S3, requiring explicit class definitions with "slots" and typed data.

R6 (via the R6 package ) provides "classical" OOP similar to Java or C++.

The first step in strategic selection is understanding the fundamental divide in R’s approach to objects: