list(...) as.list(x) is.list(x) alist(...)
list are of the form value
or tag=value.
The function returns a list composed of its arguments
with each value either tagged or untagged,
depending on how the argument was specified.
alist is like list, except in the handling of tagged
arguments with no value. These are handled as if they described
function arguments with no default (cf. formals), whereas
list simply ignores them.
as.list attempts to coerce its argument to list type.
For functions, this returns the concatenation of the list of formals
arguments and the function body. For expressions, the list of
constituent calls is returned.
is.list returns TRUE if its argument
is a list and FALSE otherwise.
To create an empty list, it is necessary to use the
function vector with a mode of "list".
vector(., mode="list"), c, for concatenation;
formals.data(cars) # create a plotting structure pts <- list(x=cars[,1], y=cars[,2]) plot(pts) # Argument lists f <- function()x formals(f) <- alist(x=, y=2, ...=) # Note the spec. of a "..." argument f