C# Unique List Testing : A little testing of collections.

Sometimes you want to create a unique lists, this can be done in various ways but since .NET3.5 a new method called HASHSET was created

Hash Set on MSDN:  http://msdn.microsoft.com/en-us/library/bb359438.aspx

Some code I can across recently used SortedList and I wanted to see how this compared to HashSet.


 So I set about testing a simple sting write and read 50,000; code below

SortedList

 
private static void RunSortedList()
        {
             SortedList SortedString = new SortedList();     
       
            // Sorted List WRITE TEST
            var SLWStart = DateTime.Now;
            for (int i = 1; i < 50000; i++)
            {
                SortedString.Add(i.ToString(), i.ToString());
            }
            var SLWStop = DateTime.Now;
            var SLWT = SLWStop - SLWStart;
            Console.WriteLine(" Sorted List Write Diff : " + SLWT.Ticks);


            /// SORTED LIST READ TEST
            var SLRStart = DateTime.Now;
            foreach (var s in SortedString)
            {
                var mystr = s.Value + " ";
            }
            var SLRStop = DateTime.Now;
            var SLRT = SLRStop - SLRStart;
            Console.WriteLine(" Sorted List Read Diff : " + SLRT.Ticks);
        }

HashSet

 private static void RunHasSet()
        {

            HashSet HashString = new HashSet();
            // Sorted List WRITE TEST
            var HSWStart = DateTime.Now;
            for (int i = 1; i < 50000; i++)
            {
                HashString.Add(i.ToString());
            }
            var HSWStop = DateTime.Now;
            var HSWT = HSWStop - HSWStart;
            Console.WriteLine(" HastSet Write Diff : " + HSWT.Ticks);


            /// SORTED LIST READ TEST
            var HSRStart = DateTime.Now;
            foreach (var s in HashString)
            {
                var mystr = s + " ";
            }
            var HSRStop = DateTime.Now;
            var HSRT = HSRStop - HSRStart;
            Console.WriteLine(" HastSet Read Diff : " + HSRT.Ticks);
        }

And just for a comparison

List 

private static void RunSortedList()
        {
             SortedList SortedString = new SortedList();
            
            // Sorted List WRITE TEST
            var SLWStart = DateTime.Now;
            for (int i = 1; i < 50000; i++)
            {
                SortedString.Add(i.ToString(), i.ToString());
            }
            var SLWStop = DateTime.Now;
            var SLWT = SLWStop - SLWStart;
            Console.WriteLine(" Sorted List Write Diff : " + SLWT.Ticks);


            /// SORTED LIST READ TEST
            var SLRStart = DateTime.Now;
            foreach (var s in SortedString)
            {
                var mystr = s.Value + " ";
            }
            var SLRStop = DateTime.Now;
            var SLRT = SLRStop - SLRStart;
            Console.WriteLine(" Sorted List Read Diff : " + SLRT.Ticks);
        }

This was run multiple times via a console

Collecion	Write	Read
HashSet	90,009	20,002
SortedList	4,780,478	70,007
List	60,006	20,002

Conclusion

HashSet is a lot faster than SortedList. List as expected was fastest when writing but HastSets was exactly as fast at reading.

Testing Issues

I did run all the tests at the same time and the results varied depending on the order they were run in.  so when testing for speed it is best to test in isolation.