Access to and Manipulation of the Formal Arguments

Usage

formals(fun=sys.function(sys.parent()))
formals(obj) <- list

Value

If fun is a function then the formal argument list to that function is returned. If fun is a character string then the function with that name is found and used. If fun is not specified then the function calling formals is used.

The assignment form sets the formals of a function to the list on the right hand side.

See Also

args for a “human–readable” version, alist, body, function.

Examples

length(formals(lm))      # the number of formal arguments
names(formals(boxplot))  # formal arguments names

f <- function(x)a+b
formals(f) <- alist(a=,b=3) # function(a,b=3)a+b
f(2) # result = 5