C＃从List< List< int>>中删除重复项 [英] C# remove duplicates from List<List<int>>

问题描述

我无法想出最有效的算法，以从 List< List< int>> 中删除​​重复项（例如（我知道这看起来像列表 int [] ，但只是为了视觉目的而这样做：

I'm having trouble coming up with the most efficient algorithm to remove duplicates from List<List<int>>, for example (I know this looks like a list of int[], but just doing it that way for visual purposes:

my_list[0]= {1, 2, 3};
my_list[1]= {1, 2, 3};
my_list[2]= {9, 10, 11};
my_list[3]= {1, 2, 3};

所以输出只是

new_list[0]= {1, 2, 3};
new_list[1]= {9, 10, 11};

让我知道，如果你有任何想法，我真的很感激。

Let me know if you have any ideas. I would really appreciate it.

推荐答案

构建自定义 EqualityComparer< List< int>>

public class CusComparer : IEqualityComparer<List<int>>
{
    public bool Equals(List<int> x, List<int> y)
    {
        return x.SequenceEqual(y);
    }

    public int GetHashCode(List<int> obj)
    {
        int hashCode = 0;

        for (var index = 0; index < obj.Count; index++)
        {
            hashCode ^= new {Index = index, Item = obj[index]}.GetHashCode();
        }

        return hashCode;
    }
}

然后，您可以使用独特的与自定义比较方法：

Then you can get the result by using Distinct with custom comparer method:

var result = my_list.Distinct(new CusComparer());

编辑：

将索引包含到方法 GetHashCode 中，以确保不同的订单不相​​等

Include the index into method GetHashCode to make sure different orders will not be equal

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