Question

Anyone have a quick method for de-duplicating a generic List in C#?

Answer 1

Perhaps you should consider using a HashSet.

From the MSDN link:

using System; using System.Collections.Generic;  class Program {     static void Main()     {         HashSet<int> evenNumbers = new HashSet<int>();         HashSet<int> oddNumbers = new HashSet<int>();          for (int i = 0; i < 5; i++)         {             // Populate numbers with just even numbers.             evenNumbers.Add(i * 2);              // Populate oddNumbers with just odd numbers.             oddNumbers.Add((i * 2) + 1);         }          Console.Write('evenNumbers contains {0} elements: ', evenNumbers.Count);         DisplaySet(evenNumbers);          Console.Write('oddNumbers contains {0} elements: ', oddNumbers.Count);         DisplaySet(oddNumbers);          // Create a new HashSet populated with even numbers.         HashSet<int> numbers = new HashSet<int>(evenNumbers);         Console.WriteLine('numbers UnionWith oddNumbers...');         numbers.UnionWith(oddNumbers);          Console.Write('numbers contains {0} elements: ', numbers.Count);         DisplaySet(numbers);     }      private static void DisplaySet(HashSet<int> set)     {         Console.Write('{');         foreach (int i in set)         {             Console.Write(' {0}', i);         }         Console.WriteLine(' }');     } }  /* This example produces output similar to the following:  * evenNumbers contains 5 elements: { 0 2 4 6 8 }  * oddNumbers contains 5 elements: { 1 3 5 7 9 }  * numbers UnionWith oddNumbers...  * numbers contains 10 elements: { 0 2 4 6 8 1 3 5 7 9 }  */