What is the difference between Set and List?

Question

What is the fundamental difference between the Set<E> and List<E> interfaces?

Answer 1

List:

Lists generally allow duplicate objects. Lists must be ordered, and are therefore accessible by index.

Implementation classes include: ArrayList, LinkedList, Vector

Set:

Sets do not allow duplicate objects. Most implementations are unordered, but it is implementation specific.

Implementation classes include: HashSet (unordered), LinkedHashSet (ordered), TreeSet (ordered by natural order or by provided comparator)

Answer 2

1.List allows duplicate values and set does'nt allow duplicates

2.List maintains the order in which you inserted elements in to the list Set does'nt maintain order. 3.List is an ordered sequence of elements whereas Set is a distinct list of elements which is unordered.

Answer 3

Set:

Cannot have duplicate values Ordering depends on implementation. By default it is not ordered Cannot have access by index

List:

Can have duplicate values Ordered by default Can have access by index

Answer 4

List is an ordered sequence of elements whereas Set is a distinct list of elements which is unordered (thank you, Quinn Taylor).

List<E>:

An ordered collection (also known as a sequence). The user of this interface has precise control over where in the list each element is inserted. The user can access elements by their integer index (position in the list), and search for elements in the list.

Set<E>:

A collection that contains no duplicate elements. More formally, sets contain no pair of elements e1 and e2 such that e1.equals(e2), and at most one null element. As implied by its name, this interface models the mathematical set abstraction.

Answer 5

A Set cannot contain duplicate elements while a List can. A List (in Java) also implies order.

Answer 6

Ordering... a list has an order, a set does not.