Uses of self referencing lists

Question

I know it is possible to create a self referencing list in languages like Python:

>>> my_list = [1,2]
>>> my_list.append(my_list)
>>> print my_list
[1,2,[...]]
>>> print my_list[0]
1
>>> print my_list[2]
[1,2,[...]]

What algorithms benefit from self referencing lists? I cannot think of one.

Thanks.

Answer 1

Self-referencing lists, and, generally speaking, circular data structures, can be caused when representing a graph using data structures.

For example, consider this naive representation of a graph: Each node is either an atomic value, or a list of nodes that it is linked to. A circle may cause a list to contain another list that contains the list. A self-circle, i.e., an edge from a node to itself, will cause a self-referencing list.