Learn R Programming

base (version 3.1.0)

get: Return the Value of a Named Object

Description

Search by name for an object (get) or zero or more objects (mget).

Usage

get(x, pos = -1, envir = as.environment(pos), mode = "any", inherits = TRUE)
mget(x, envir = as.environment(-1), mode = "any", ifnotfound, inherits = FALSE)

Arguments

x
For get, an object name (given as a character string). For mget, a character vector of object names.
pos, envir
where to look for the object (see ‘Details’); if omitted search as if the name of the object appeared unquoted in an expression.
mode
the mode or type of object sought: see the ‘Details’ section.
inherits
should the enclosing frames of the environment be searched?
ifnotfound
A list of values to be used if the item is not found: it will be coerced to a list if necessary.

Value

For get, the object found. If no object is found an error results.For mget, a named list of objects (found or specified via ifnotfound).

Details

The pos argument can specify the environment in which to look for the object in any of several ways: as a positive 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 default of -1 indicates the current environment of the call to get. The envir argument is an alternative way to specify an environment.

These functions look to see if each of the name(s) x have a value bound to it in the specified environment. If inherits is TRUE and a value is not found for x in the specified environment, the enclosing frames of the environment are searched until the name x is encountered. See environment and the ‘R Language Definition’ manual for details about the structure of environments and their enclosures.

If mode is specified then only objects of that type are sought. mode here is a mixture of the meanings of typeof and mode: "function" covers primitive functions and operators, "numeric", "integer" and "double" all refer to any numeric type, "symbol" and "name" are equivalent but "language" must be used (and not "call" or "(").

For mget, the values of mode and ifnotfound can be either the same length as x or of length 1. The argument ifnotfound must be a list containing either the value to use if the requested item is not found or a function of one argument which will be called if the item is not found, with argument the name of the item being requested.

References

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

See Also

exists, assign.

Examples

Run this code
get("%o%")

## test mget
e1 <- new.env()
mget(letters, e1, ifnotfound = as.list(LETTERS))

Run the code above in your browser using DataLab