formals
Access and Manipulate the Formal Arguments
Description
Gets or sets the formal arguments of a function.
Usage
formals(fun = sys.function(sys.parent()), envir = parent.frame())
formals(fun, envir = parent.frame()) <- value
Arguments
| fun |
a function object.
|
| envir |
an environment where the function is defined.
|
| value |
a list of expressions with named elements. The element
names are the argument names and the values are the default
argument values.
|
Details
When you call the function formals(), you can set the
funargument to a character string giving the name of a function.
Value
returns a list where element names are the argument names, and their values
are the default argument values.
Side Effects
The assignment function sets the formal arguments of the function to the
list on the right-hand side. No consistency with current argument names or
number is enforced or checked. All existing arguments are replaced by
the new list of arguments.
See Also
Examples
# Getting names of formal arguments
names(formals(sample))
# Setting formal arguments
func <- function(x) a + b
formals(func) <- list(a = NULL, b = 3)
func(10)