| formals {base} | R Documentation |
Get or set the formal arguments of a function.
formals(fun = sys.function(sys.parent())) formals(fun, envir = environment(fun)) <- value
fun |
a function object, or see Details. |
envir |
environment in which the function should be defined. |
value |
a list (or pairlist) of R expressions. |
For the first form, fun can also be a character string
naming the function to be manipulated, which is searched for from the
parent environment.
If it is not specified, the function calling formals is used.
Only closures have formals, not primitive functions.
formals returns the formal argument list of the function
specified, as a pairlist, or NULL for a
non-function or primitive.
The replacement form sets the formals of a function to the
list/pairlist on the right hand side, and (potentially) resets the
environment of the function.
args for a “human-readable” version,
alist,
body,
function.
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