Question

What would you recommend for class that needs to keep a list of unique integers?

I’m going to want to Add() integers to the collection and also check for existence e.g. Contains().

Would be nice to also get them in a list as a string for display, ie. ‘1, 5, 10, 21’.

Answer 1

HashSet:

The HashSet<T> class provides high-performance set operations. A set is a collection that contains no duplicate elements, and whose elements are in no particular order…

The capacity of a HashSet<T> object is the number of elements that the object can hold. A HashSet<T> object’s capacity automatically increases as elements are added to the object.

The HashSet<T> class is based on the model of mathematical sets and provides high-performance set operations similar to accessing the keys of the Dictionary<TKey, TValue> or Hashtable collections. In simple terms, the HashSet<T> class can be thought of as a Dictionary<TKey, TValue> collection without values.

A HashSet<T> collection is not sorted and cannot contain duplicate elements…