.NET FAQ - Removing Duplicates with LINQ

If you need to remove duplicates from an IEnumerable (array, List<T>, etc.), you can use the Distinct LINQ extension method from the Enumerable class in the System.Linq namespace to make the job extremely easy.

In addition to the Distinct method, the IEnumerable extension methods provide multiple useful methods for doing things like sorting, calculating min and max, and much more.

Removing Duplicates Examples

var listWithDuplicates1 = new List<int>() { 1, 2, 3, 1, 2, 3 };
var distinct1 = listWithDuplicates1.Distinct();

var listWithDuplicates2 = new List<string>() { "Tom", "Joe", "Sally", "Tom" };
var distinct2 = listWithDuplicates2.Distinct();

var arrayWithDuplicates = new string[] { "Tom", "Joe", "Sally", "Tom" };
var distinct3 = arrayWithDuplicates.Distinct();