Distinct

　　Distinct去除一个序列里相同的元素。用法如下代码：

static void Main()
{
    List&ltint&gt ages = new List&ltint&gt { 21, 46, 46, 55, 17, 21, 55, 55 };
    //Distinct的用法
    IEnumerable&ltint&gt distinctAges = ages.Distinct();
    Console.WriteLine("Distinct ages:");
    foreach (int age in distinctAges)
    {
        Console.WriteLine(age);
    }
}

运行结果为：

Distinct ages:
21
46
55
17