get
) or zero or more objects
(mget
).
get(x, pos = -1, envir = as.environment(pos), mode = "any", inherits = TRUE)
mget(x, envir = as.environment(-1), mode = "any", ifnotfound, inherits = FALSE)
dynGet(x, ifnotfound = , minframe = 1L, inherits = FALSE)
get
, an object name (given as a character
string).
For mget
, a character vector of object names.
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.
dynGet()
is somewhat experimental and to be used inside
another function. It looks for an object in the callers, i.e.,
the sys.frame()
s of the function. Use with caution.
exists
for checking whether an object exists;
get0
for an efficient way of both checking existence and
getting an object. assign
, the inverse of get()
, see above.
Use getAnywhere
for searching for an object
anywhere, including in other namespaces, and
getFromNamespace
to find an object in a specific
namespace.
get("%o%")
## test mget
e1 <- new.env()
mget(letters, e1, ifnotfound = as.list(LETTERS))
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