R objects

The following functions are useful to explore the »internals« of an object:

• dim
• class
• mode
• str displays the internal structure of an object
• summary
• typeof

Some functions allow to get some characteristics of the data itself:

• View and tail
• head
• glimpse (tidyverse?)
• table and unique

See also the package lobstr

All R objects, except the special NULL object, can have one or more attributes attached to it. These are stored as a pairlist.

R Objects are accessed via symbols or variables (Is variable the same thing as a symbol?).

Symbols are also objects.

Symbols have the mode name, storage mode symbol and type symbol.

An expression objects contains one or more parsed but unevaluated statements.

Expression objects are very similar to lists.

In the source code of R, an object is a pointer to a structure with typedef SEXPREC.

The different datatypes are represented by SEXPTYPE (which is a typedef'd unsigned int, see src/include/Rinternals.h).

An object can be serialized with serialize, save or saveRDS and be deserialzed with unserialize, load or loadRDS.

R has three object oriented systems: S3, S4 and S5

class, mode

identical(obj_1, obj_2) tests if two objects are exactly equal.

Functions are objects, too.

The NULL object.

dput dumps an object in the form of R code.