[…] The SAS/IML language supports lists, which are containers that store other objects, such as matrices and other lists. A primary use of lists is to pack objects of various types into a single symbol that can be passed to and from modules. A useful feature of using lists is that lists can dynamically grow or shrink as necessary. You can use the ListAddItem subroutine to add a new item to an existing list, which can be convenient if you do not know until run time how many items the list needs to hold. …