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(paste("value for '", x, "' not found", sep = ""), 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 of object sought. |
inherits |
should the enclosing frames of the environment be searched? |
ifnotfound |
A list of values to be used if the item is
not found. |
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.
The mode
may specify collections such as "numeric"
and
"function"
: 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. The argument is 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=LETTERS)