environment {base}R Documentation

Environment Access


Get, set, test for and create environments.


environment(fun = NULL)
environment(fun) <- value




new.env(hash = FALSE, parent = parent.frame(), size = 29L)

parent.env(env) <- value




fun a function, a formula, or NULL, which is the default.
value an environment to associate with the function
x an arbitrary R object.
hash a logical, if TRUE the environment will be hashed
parent an environment to be used as the enclosure of the environment created.
env an environment
size an integer specifying the initial size for a hashed environment. An internal default value will be used if size is NA or zero. This argument is ignored if hash is FALSE.


Environments consist of a frame, or collection of named objects, and a pointer to an enclosing environment. The most common example is the frame of variables local to a function call; its enclosure is the environment where the function was defined. The enclosing environment is distinguished from the parent frame: the latter (returned by parent.frame) refers to the environment of the caller of a function.

When get or exists search an environment with the default inherits = TRUE, they look for the variable in the frame, then in the enclosing frame, and so on.

The global environment .GlobalEnv, more often known as the user's workspace, is the first item on the search path. It can also be accessed by globalenv(). On the search path, each item's enclosure is the next item.

The object .BaseNamespaceEnv is the name space environment for the base package. The environment of the base package itself is available as baseenv(). The ultimate enclosure of any environment is the empty environment emptyenv(), to which nothing may be assigned. If one follows the parent.env() chain of enclosures back far enough from any environment, eventually one reaches the empty environment.

The replacement function parent.env<- is extremely dangerous as it can be used to destructively change environments in ways that violate assumptions made by the internal C code. It may be removed in the near future.


If fun is a function or a formula then environment(fun) returns the environment associated with that function or formula. If fun is NULL then the current evaluation environment is returned.
The replacement form sets the environment of the function or formula fun to the value given.
is.environment(obj) returns TRUE if and only if obj is anenvironment.
new.env returns a new (empty) environment enclosed in the parent's environment, by default.
parent.env returns the parent environment of its argument.
parent.env<- sets the enclosing environment of its first argument.
environmentName returns a character string, that given when the environment is printed or "" if it is not a named environment.
env.profile returns a list with the following components: size the number of chains that can be stored in the hash table, nchains the number of non-empty chains in the table (as reported by HASHPRI), and counts an integer vector giving the length of each chain (zero for empty chains). This function is intended to assess the performance of hashed environments. When env is a non-hashed environment, NULL is returned.

See Also

The envir argument of eval, get, and exists.

ls may be used to view the objects in an environment, and hence ls.str may be useful for an overview.

sys.source can be used to “fill” an environment.


f <- function() "top level function"

##-- all three give the same:

ls(envir=environment(approxfun(1:2,1:2, method="const")))

is.environment(.GlobalEnv) # TRUE

e1 <- new.env(parent = baseenv())  # this one has enclosure package:base.
e2 <- new.env(parent = e1)
assign("a", 3, env=e1)
exists("a", env=e2)     # this succeeds by inheritance
exists("a", env=e2, inherits = FALSE)
exists("+", env=e2)     # this succeeds by inheritance

[Package base version 2.5.0 Index]