R in a Nutshell, 2nd Edition

Working with Environments

Like everything else in R, environments are objects. Internally, R stores symbol mappings in hash tables. In Chapter 24, I’ll show how some tricks for using environment objects to write efficient R code.

Table 8-1 shows the functions in R for manipulating environment objects.

Table 8-1. Manipulating environment objects

Function	Description
assign	Assigns the name x to the object value in the environment envir.
get	Gets the object associated with the name x in the environment envir.
exists	Checks that the name x is defined in the environment envir.
objects	Returns a vector of all names defined in the environment envir.
remove	Removes the list of objects in the argument list from the environment envir. (List is an unfortunate argument name, especially as the argument needs to be a vector.)
search	Returns a vector containing the names of attached packages. You can think of this as the search path in which R tries to resolve names. More precisely, it shows the list of chained parent environments.
searchpaths	Returns a vector containing the paths of attached packages.
attach	Adds the objects in the list, data frame, or data file what to the current search path.
detach	Removes the objects in the list, data frame, or data file what from the current search path.
emptyenv	Returns the empty environment object. All environments chain back to this object.
parent.env	Returns the parent of environment env.
baseenv	The environment of the base package.
globalenv or .GlobalEnv	Returns the environment ...