在Java中获取二维数组的数组长度 [英] Getting the array length of a 2D array in Java

问题描述

我需要获取行和列的二维数组的长度.我已经成功地做到了这一点，使用以下代码:

I need to get the length of a 2D array for both the row and column. I’ve successfully done this, using the following code:

public class MyClass {

 public static void main(String args[])
    {
  int[][] test; 
  test = new int[5][10];

  int row = test.length;
  int col = test[0].length;

  System.out.println(row);
  System.out.println(col);
    }
}

这会按预期打印出 5、10.

This prints out 5, 10 as expected.

现在看看这一行:

  int col = test[0].length;

请注意，我实际上必须引用特定行，才能获得列长度.对我来说，这看起来非常丑陋.此外，如果数组定义为:

Notice that I actually have to reference a particular row, in order to get the column length. To me, this seems incredibly ugly. Additionally, if the array was defined as:

test = new int[0][10];

然后代码在尝试获取长度时会失败.有没有其他(更智能)的方法来做到这一点?

Then the code would fail when trying to get the length. Is there a different (more intelligent) way to do this?

推荐答案

考虑

public static void main(String[] args) {

    int[][] foo = new int[][] {
        new int[] { 1, 2, 3 },
        new int[] { 1, 2, 3, 4},
    };

    System.out.println(foo.length); //2
    System.out.println(foo[0].length); //3
    System.out.println(foo[1].length); //4
}

每行的列长度不同.如果您通过固定大小的 2D 数组支持某些数据，则为包装类中的固定值提供 getter.

Column lengths differ per row. If you're backing some data by a fixed size 2D array, then provide getters to the fixed values in a wrapper class.

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