data structures - Array versus linked-list

Question

Why would someone want to use a linked-list over an array?

Coding a linked-list is, no doubt, a bit more work than using an array and one may wonder what would justify the additional effort.

I think insertion of new elements is trivial in a linked-list but it's a major chore in an array. Are there other advantages to using a linked list to store a set of data versus storing it in an array?

This question is not a duplicate of this question because the other question is asking specifically about a particular Java class while this question is concerned with the general data structures.

Answer 1

Another good reason is that linked lists lend themselves nicely to efficient multi-threaded implementations. The reason for this is that changes tend to be local - affecting only a pointer or two for insert and remove at a localized part of the data structure. So, you can have many threads working on the same linked list. Even more, it's possible to create lock-free versions using CAS-type operations and avoid heavy-weight locks altogether.

With a linked list, iterators can also traverse the list while modifications are occurring. In the optimistic case where modifications don't collide, iterators can continue without contention.

With an array, any change that modifies the size of the array is likely to require locking a large portion of the array and in fact, it's rare that this is done without a global lock across the whole array so modifications become stop the world affairs.