c# - 多维数组列排序

Question

假设我创建此代码以生成第 idv 个随机数。但是我很难根据最后一列对数组进行排序。

假设单个尺寸是 [idv, width] = [8,6] 我想对第 6 列的所有行进行排序...我想在排序后获取数组中的第 4 个列表。我怎样才能将这种情况实现到代码中？

public static void population(double[,] individual, int width, int idv, Random rnd)
    {
        for (int i = 0; i < idv; i++)
        {
            Console.Write("individual {0} :\t", i+1);
            for (int j = 0; j < width; j++)
            {
                individual[i, j] = Math.Round(rnd.NextDouble() * 10, 2);
                Console.Write("{0} ", individual[i, j]);
            }
            Console.WriteLine("\n");
        }
    }

谢谢

Answer 1

我建议你使用交错数组 double[][] 而不是2d double[,] .锯齿状数组只是一个数组的数组，您通常可以借助 Linq 轻松地对其进行排序、过滤等:

  double[][] individual = new double[][] {
    new double[] {81, 82, 83, 84, 85, 86},
    new double[] {11, 12, 13, 14, 15, 16},
    new double[] {41, 42, 43, 44, 45, 46},
    new double[] {31, 32, 33, 34, 35, 36},
    new double[] {51, 52, 53, 54, 55, 56},
    new double[] {21, 22, 23, 24, 25, 26},
    new double[] {61, 62, 63, 64, 65, 66},
    new double[] {71, 72, 73, 74, 75, 76},
  };

  double[][] fragment = individual
    .OrderBy(line => line[line.GetUpperBound(0)]) // by last column
    .Take(4) 
    .ToArray();

再来一个Linq来测试结果:

  String test = String.Join(Environment.NewLine, fragment
    .Select(line => String.Join("\t", line)));

  Console.Write(test);

结果是

11  12  13  14  15  16
21  22  23  24  25  26
31  32  33  34  35  36
41  42  43  44  45  46