Linked list library

The Linked list library is a library that comes with Analytica. To use it, you must add the library to your model by selecting Add Library... from the File menu. You can either Link or Embed the library, it shouldn't make much difference.

Alternatives

A linked list is a data structure that is not the same as an Analytica list or array. You can "push" something on the front of a normal Analytica list using Concat(x,L) which in many cases is more direct, or on the rear of a list using Concat(L,x). However, when doing so, the elements of the list are copied with each push. When a large number of items are "pushed" onto a normal list in this fashion, your algorithm ends up with an [math]\displaystyle{ O(n^2) }[/math] time complexity. Using a linked list enables you to push n items in [math]\displaystyle{ O(n) }[/math] time.

Another alternative is to use an array. Start with an index, I that has more than the maximum number of items you would ever have in your collection, and then use slice assignment to add items to the array. This takes the form:

Var a := null;
Var n := 0;
a[ I = (n := n+1) ] := 'a';   { Add 'a' as first element }
a[ I = (n := n+1) ] := 'b';   { Add 'b' as second element }
...

Using an array with Slice assignment in this fashion is likely to be the most efficient method, but it does require you to have a bound on the maximum number of elements that can ever be in the collection, whereas when using a linked list, no such assumptions are necessary.