Primitive Object Types
Table 7-1 shows all of the built-in object types. I introduced these objects in Chapter 3, so they should seem familiar. I classified the object types into a few categories, to make them easier to understand.
- Basic vectors
These are vectors containing a single type of value: integers, floating-point numbers, complex numbers, text, logical values, or raw data.
- Compound objects
These objects are containers for the basic vectors: lists, pairlists, S4 objects, and environments. Each of these objects has unique properties (described below), but each of them contains a number of named objects.
- Special objects
These objects serve a special purpose in R programming:
.... Each of these means something important in a specific context, but you would never create an object of these types.
- R language
These are objects that represent R code; they can be evaluated to return other objects.
Functions are the workhorses of R; they take arguments as inputs and return objects as outputs. Sometimes, they may modify objects in the environment or cause side effects outside the R environment like plotting graphics, saving files, or sending data over the network.
These are object types that are formally defined by R, but which aren’t normally accessible within the R language. In normal R programming, you will probably never encounter any of the objects.
We’ll explore what each of these objects is used for in this chapter.
Table 7-1. Primitive object types in R ...