Matlab has an aggregate variable called a structure, which consists of
component variables each of which can be of a different data type and
dimension. For example, I can have a single structure Model which
consists of Model.variable1, Model.variable2, and Model.variable3,
where variable1 is a string variable, variable 2 is a 1x24 vector, and
variable 3 is a 6x6x6 array. The benefit is that the aggregate
variable Model can be passed between programs without having to pass
each of the component variables. Does R have anything similar?