assign {base}R Documentation

Assign a Value to a Name

Description

Assign a value to a name in an environment.

Usage

assign(x, value, pos = -1, envir = as.environment(pos),
       inherits = FALSE, immediate = TRUE)

Arguments

x a variable name (given as a quoted string in the function call).
value a value to be assigned to x.
pos where to do the assignment. By default, assigns into the current environment. See the details for other possibilities.
envir the environment to use. See the details section.
inherits should the enclosing frames of the environment be inspected?
immediate an ignored compatibility feature.

Details

The pos argument can specify the environment in which to assign the object in any of several ways: as an integer (the position in the search list); as the character string name of an element in the search list; or as an environment (including using sys.frame to access the currently active function calls). The envir argument is an alternative way to specify an environment, but is primarily there for back compatibility.

assign does not dispatch assignment methods, so it cannot be used to set elements of vectors, names, attributes, etc.

Note that assignment to an attached list or data frame changes the attached copy and not the original object: see attach.

Value

This function is invoked for its side effect, which is assigning value to the variable x. If no envir is specified, then the assignment takes place in the currently active environment.
If inherits is TRUE, enclosing environments of the supplied environment are searched until the variable x is encountered. The value is then assigned in the environment in which the variable is encountered. If the symbol is not encountered then assignment takes place in the user's workspace (the global environment).
If inherits is FALSE, assignment takes place in the initial frame of envir.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

<-, get, exists, environment.

Examples

for(i in 1:6) { #-- Create objects  'r1', 'r2', ... 'r6' --
 nam <- paste("r",i, sep=".")
 assign(nam, 1:i)
}
ls(pat="^r..$")

##-- Global assignment within a function:
myf <- function(x) {
 innerf <- function(x) assign("Global.res", x^2, env = .GlobalEnv)
 innerf(x+1)
}
myf(3)
Global.res # 16

a <- 1:4
assign("a[1]", 2)
a[1] == 2          #FALSE
get("a[1]") == 2   #TRUE


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