What collections with Set interface exist?

Collections with the Set interface are data structures that store unique elements without a specific order (or with a specific one, depending on the implementation).

Different languages and libraries have different implementations:

• Java: HashSet, LinkedHashSet, TreeSet — all implement the Set interface.
• Python: built-in set type.
• C#: HashSet<T>, SortedSet<T>.
• JavaScript: Set object.

In the context of QA/automation, such collections can be used to store unique values, such as unique identifiers, to avoid duplication in tests.

When it comes to automation tools, data structures provided by the programming language, such as sets in Python or HashSet in Java, are often used to implement logic with unique elements.