如何将Arraylist转换为2D double[][]数组

import java.util.ArrayList;

public class ArrayListTo2DArray {
    public static void main(String[] args) {
        ArrayList<Double> list = new ArrayList<>();
        list.add(1.1);
        list.add(2.2);
        list.add(3.3);
        
        double[][] array = arrayListTo2DArray(list);
        
        // 打印转换后的二维数组
        for (int i = 0; i < array.length; i++) {
            for (int j = 0; j < array[0].length; j++) {
                System.out.print(array[i][j] + " ");
            }
            System.out.println();
        }
    }
    
    public static double[][] arrayListTo2DArray(ArrayList<Double> list) {
        int rows = list.size();
        double[][] array = new double[rows][];
        
        for (int i = 0; i < rows; i++) {
            double[] row = new double[1];  // 假设每一行只有一个元素
            row[0] = list.get(i);
            array[i] = row;
        }
        
        return array;
    }
}

1.1
2.2
3.3