【datagridview中】
      ID    NAME   VALUE
      1    兔子     3
      2     兔子    5
      3     猫      2
      4     猫      4
      5     猫      1
      6     狗      5
    ...    ...    ...
     【问题】我想把属于一类的值放到一个数组里面，应该怎么做例如：[3,5],[2,4,1][5]
           int n = this.dataGridView1.Rows.Count;
            ArrayList nums = new ArrayList();
            for (int i = 0; i < n;i++ )
            {
                String stringValue = this.dataGridView1.Rows[i].Cells[1].Value as string;
                switch (stringValue)
                {
                    case "兔子":
                        double a = Convert.ToDouble(dataGridView1.Rows[i].Cells[2].Value);
                        nums[i] = a;      【报错】索引超出范围。必须为非负值并小于集合大小。参数名: index
                        break;  
                    case "猫":
                        double b = Convert.ToDouble(dataGridView1.Rows[i].Cells[2]);
                        nums[i] = b;
                        break;
                    case "狗":
                        double c = Convert.ToDouble(dataGridView1.Rows[i].Cells[2]);
                        nums[i] = c;
                        break;
具体应该怎么改，请详细解释下，谢谢！

把ArrayList nums = new ArrayList();这行代码改成数组
double[] nums = new double[n];

nums.add(值)