Defaults {quantmod} | R Documentation |
Manage Default Argument Values for quantmod Functions
Description
Use globally specified defaults, if set, in place of formally specified default argument values. Allows user to specify function defaults different than formally supplied values, e.g. to change poorly performing defaults, or satisfy a different preference.
Usage
setDefaults(name, ...)
unsetDefaults(name, confirm = TRUE)
getDefaults(name = NULL, arg = NULL)
importDefaults(calling.fun)
Arguments
name |
name of function, quoted or unquoted (see Details) |
... |
name=value default pairs |
confirm |
prompt before unsetting defaults |
arg |
values to retrieve |
calling.fun |
name of function to act upon |
Details
- setDefaults
-
Provides a wrapper to R
options
that allows the user to specify any name=value pair for a function's formal arguments. Only formal name=value pairs specified will be updated.Values do not have to be respecified in subsequent calls to
setDefaults
, so it is possible to add new defaults for each function one at a time, without having to retype all previous values. AssigningNULL
to any argument will remove the argument from the defaults list.name
can be an unquoted, bare symbol only at the top-level. It must be a quoted character string if you callsetDefaults
inside a function. - unsetDefaults
-
Removes name=value pairs from the defaults list.
- getDefaults
-
Provides access to the stored user defaults. Single arguments need not be quoted, multiple arguments must be in a character vector.
- importDefaults
-
A call to
importDefaults
should be placed on the first line in the body of the function. It checks the user's environment for globally specified default values for the called function. These defaults can be specified by the user with a call tosetDefaults
, and will override any default formal parameters, in effect replacing the original defaults with user supplied values instead. Any user-specified values in the parent function (that is, the function containingimportDefaults
) will override the values set in the global default environment.
Value
setDefaults |
None. Used for it's side effect of setting a list of default arguments by function. |
unsetDefaults |
None. Used for it's side effect of unsetting default arguments by function. |
getDefaults |
A named list of defaults and associated values, similar to
This does not imply that the returned function names are able
to accept defaults (via |
importDefaults |
None. Used for its side-effect of loading all non- |
Note
- setDefaults
-
At present it is not possible to specify
NULL
as a replacement for a non-NULL
default, as the process interpretsNULL
values as being not set, and will simply use the value specified formally in the function. IfNULL
is what is desired, it is necessary to include this in the function call itself.Any arguments included in the actual function call will take precedence over
setDefaults
values, as well as the standard formal function values. This conforms to the current user experience in R.Like
options
, default settings are not kept across sessions. Currently, it is not possible to pass values for ... arguments, only formally specified arguments in the original function definition. - unsetDefaults
-
unsetDefaults
removes the all entries from theoptions
lists for the specified function. To remove single function default values simply set the name of the argument toNULL
insetDefaults
. - importDefaults
-
When a function implements
importDefaults
, non-named arguments may be ignored if a global default has been set (i.e. notNULL
). If this is the case, simply name the arguments in the calling function.This should also work for functions retrieving formal parameter values from
options
, as it assigns a value to the parameter in a way that looks like it was passed in the function call. So any check onoptions
would presumably disregardimportDefaults
values if an argument was passed to the function.
Author(s)
Jeffrey A. Ryan
See Also
Examples
my.fun <- function(x=3)
{
importDefaults('my.fun')
x^2
}
my.fun() # returns 9
setDefaults(my.fun, x=10)
my.fun() # returns 100
my.fun(x=4) # returns 16
getDefaults(my.fun)
formals(my.fun)
unsetDefaults(my.fun, confirm=FALSE)
getDefaults(my.fun)
my.fun() # returns 9