get: Return the Value of a Named Object
Description Usage Arguments Details Value Note References See Also ExamplesDescription
Search by name for an object [get] or zero or more objects [mget].
Usage
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7 | 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]
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Arguments
| x | For get, an object name [given as a character string]. |
| 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 | For mget, a list of values to be used if the item is not found: it will be coerced to a list if necessary. |
| minframe | integer specifying the minimal frame number to look into. |
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.
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.
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].
Note
The reverse [or inverse] of a