Sam Gentile's Blog (if (DeveloperTask == Communication && OS == Windows)

This is part of a series. To add to 3.5's new HashSet<T>, there is now SortedSet<T> new in 4.0. Both have the following distinguishing features:

• Their Contains methods execute quickly using a hash-based lookup
• They do not store duplicate elements and silently ignore requests to add duplicates
• You cannot access an element by position

SortedSet<T> keeps elements in order, whereas HashSet<T> does not. HashSet<T> is implemented wuth a hashtable that just stores keys;SortedSet<T> is implemented with a red/black tree.

You can consult MSDN for the definition of HashSet but SortedSet<T> adds:

• public virtual SortedSet<T> GetViewBetween(T lowerValue, T upperValue)
• public IEnumerable<T> Reverse()
• public T Min( get; )
• public T Max( get; )

Let's see how to use some of SortedSet<T>:

using System;

using System.Collections.Generic;

 
namespace SortedSet

{

    class Program

    {

        static void Main(string[] args)

        {

            // Loading letters into a SortedSet<char> and

            // enumerating the characters

            var letters = new SortedSet<char>("the quick brown fox");

            foreach (char c in letters) Console.Write(c);  // bcefhiknoqrtuwx

 
            // Get the letters between f and j

            foreach(char c in letters.GetViewBetween('f', 'j'))

                Console.WriteLine(c);

 
            // Destructive set operators modify the original collection

            // UnionWith adds all the elements in the 2nd set to the 

            // original (excluding duplicates)

            // IntersectsWith removes all the elements that are not

            // in both sets

            letters.IntersectWith("aeiou");

            foreach(char c in letters) Console.Write(c);   // euio

 
            // Strip all vowels with ExceptWith

            var letters2 = new SortedSet<char>("aeiou");

            foreach(char c in letters2) Console.Write(c);

 
            // SymmmetricExcerptWith removes all but the elements 

            // that are unique to one set or other

            var letters3 = new SortedSet<char>("the quick brown fox");

            letters3.SymmetricExceptWith("the lazy brown fox");

            foreach(char c in letters3) Console.Write(c);   

        }

    }

}