Question

我有一个二维数组我需要使用Java复制2d数组的每一行和每一列，如下所示（覆盖现有值，而不创建新的列/行）：

当前方法

     for(int i = 0; i < result.get(z).getWidth()-2; i+=1)
    {   for(int j = 0; j < result.get(z).getHeight()-2; j+=1)
    {   
        x[i+1][j] = result.get(z).getRGB(i, j);
        x[i][j+1] = result.get(z).getRGB(i, j);
        x[i+1][j+1] = result.get(z).getRGB(i, j);




    }

}

Answer 1

替代方法：

private static void duplicateAlternates(int[][] matrix) {
    for (int row = 0; row < matrix.length; row += 2)
        for (int col = 1; col < matrix.length; col += 2)
            matrix[row][col] = matrix[row][col - 1];
    for (int row = 1; row < matrix.length; row += 2)
        for (int col = 0; col < matrix.length; col++)
            matrix[row][col] = matrix[row - 1][col];
}

测试

public static void main(String[] args) {
    int[][] matrix = { {  10,  17, 200, 255,   0 },
                       {   0, 199, 100,  30,  45 },
                       { 250,  23, 177, 180,  79 },
                       {   0,   9,  14, 150,  70 },
                       {  50,  55, 187,  10, 233 } };
    print(matrix);
    duplicateAlternates(matrix);
    print(matrix);
}
private static void print(int[][] matrix) {
    for (int row = 0; row < matrix.length; row++) {
        for (int col = 0; col < matrix[row].length; col++)
            System.out.printf(" %3d", matrix[row][col]);
        System.out.println();
    }
    System.out.println();
}

输出

  10  17 200 255   0
   0 199 100  30  45
 250  23 177 180  79
   0   9  14 150  70
  50  55 187  10 233

  10  10 200 200   0
  10  10 200 200   0
 250 250 177 177  79
 250 250 177 177  79
  50  50 187 187 233

Answer 2

使用if / else的另一种方法：

private static void duplicateAlternatesWithIfElse(int[][] matrix) {
        for (int row = 0; row < matrix.length; row++) {
            for (int col = 0; col < matrix.length; col++) {
                if ((row - 1) % 2 == 0) {
                    matrix[row][col] = matrix[row - 1][col];
                } else if ((col - 1) % 2 == 0) {
                    matrix[row][col] = matrix[row][col - 1];
                }
            }
        }
    }

使用主要功能进行测试：

public static void main(String[] args) {
        int[][] twoDimArray = { 
                { 10, 17, 200, 255, 0 }, 
                { 0, 199, 100, 30, 45 }, 
                { 250, 23, 177, 180, 79 },
                { 0, 9, 14, 150, 70 }, 
                { 50, 55, 187, 10, 233 } 
        };

        printMatrix(twoDimArray);
        duplicateAlternatesWithIfElse(twoDimArray);
        printMatrix(twoDimArray);

    }

输出：

  10  17 200 255   0
   0 199 100  30  45
 250  23 177 180  79
   0   9  14 150  70
  50  55 187  10 233

  10  10 200 200   0
  10  10 200 200   0
 250 250 177 177  79
 250 250 177 177  79
  50  50 187 187 233

复制Java中2d数组的每一行和每一列

2 个答案: