.NET-list扩展方法Distinct去重

.NET中list的扩展方法Distinct可以去掉重复的元素，分别总结默认去重和自定义去重。

   class Program
    {
        static void Main(string[] args)
        {
            //Distinct去重

            //默认去重
            List<int> list1 = new List<int> {3, 9, 2, 3, 9};
            List<int> list2 = list1.Distinct().ToList(); //出去重复元素，列表变为{3,9,2}

            //自定义去重
            List<Test> list3 = new List<Test>();
            list3.Add(new Test(){Data=3});
            list3.Add(new Test() { Data = 9 });
            list3.Add(new Test() { Data = 2 });
            list3.Add(new Test() { Data = 3 });
            list3.Add(new Test() { Data = 9 });
            List<Test> list4 = list3.Distinct(new TestDuplicateDefine()).ToList();//变为3项
        }

        public class Test
        {
            public int Data { get; set; }
        }

        public class TestDuplicateDefine: IEqualityComparer<Test>
        {
            public bool Equals(Test x, Test y)
            {
                return x.Data == y.Data;
            }

            public int GetHashCode(Test obj)
            {
                return obj.ToString().GetHashCode();
            }
        }

    }

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