| get {base} | R Documentation |
Search for an R object with a given name and return it.
get(x, pos = -1, envir = as.environment(pos), mode = "any",
inherits = TRUE)
mget(x, envir, mode = "any",
ifnotfound = list(function(x)
stop(paste0("value for '", x, "' not found"),
call. = FALSE)),
inherits = FALSE)
x |
a variable name (given as a character string). |
pos |
where to look for the object (see the details section); if omitted, the function will search as if the name of the object appeared unquoted in an expression. |
envir |
an alternative way to specify an environment to look in; see the ‘Details’ section. |
mode |
the mode or type of object sought: see the ‘Details’ section. |
inherits |
should the enclosing frames of the environment be searched? |
ifnotfound |
A |
The pos argument can specify the environment in which to look
for 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.
This function looks to see if the name x has 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.
Warning:
inherits = TRUE is the default behaviour for R but not for S.
If mode is specified then only objects of that type are sought.
The mode may specify one of the collections "numeric" and
"function" (see mode): any member of the
collection will suffice.
Using a NULL environment is equivalent to using the current
environment.
For mget multiple values are returned in a named
list. This is true even if only one value is requested. The
value in mode and ifnotfound can be either the same length
as the number of requested items 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. The default value for inherits is
FALSE, in contrast to the default behavior for get.
mode here is a mixture of the meanings of typeof
and mode: "function" covers primitive functions
and operators, "numeric", "integer", "real"
and "double" all refer to any numeric type, "symbol" and
"name" are equivalent but "language" must be used.
The object found. (If no object is found an error results.)
The reverse of a <- get(nam) is assign(nam, a).
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
get("%o%")
##test mget
e1 <- new.env()
mget(letters, e1, ifnotfound = as.list(LETTERS))