List
A list is a sequence of scalar values enclosed in parentheses. The following is a simple example of a list:
(1, 5.3, “hello”, 2)
This list contains four elements, each of which is a scalar value: the numbers 1 and 5.3, the string hello, and the number 2.
Lists can be as long as needed, and they can contain any scalar value. A list can have no elements at all, as follows:
()
This list also is called an empty list.
NOTE
A list with one element and a scalar value are different entities. For example, the list
(43.2)
and the scalar value
43.2
are not the same thing. This is not a limitation because one can be converted to or assigned to the other.