Modes of Objects
R objects exist within an object system. R has two object systems: S3 and S4. S4 is the newest version of R and contains a new way to approach R programming. S3 is the preceding version. Both versions run concurrently. S4 offers powerful new methods, but to use those methods a solid knowledge of S3 is necessary. This book focuses mainly on S3 methods, including S4 syntax where appropriate.
Overview of the Modes
Modes describe the type of information an object contains and are an S3-level classification. The mode of an object can be found by using the function mode(). The S4 level classification is by type and can be ...