R objects exist within an object system. R has three object systems of which this book covers two: S3 and S4. S4 is a newer version of R and contains a new way to approach R programming. S3 is an earlier version. Both versions run concurrently. S4 offers powerful new methods, but to use those methods a solid knowledge of S3 is necessary. This book includes S4 syntax but focuses on S3 syntax.
Overview of the Modes and Types
Modes describe the kind of information an object contains and are an S3-level classification. The mode of an object can be found by using the function ...
