打印3D数组中的所有值

Question

Is there a way to print all values in a 3d array?

This is what I got but getting a null pointer exception:

        int i = 2;
        int x = 15;
        String[][][] arrays = new String[x][x][i];
        String arraytext = "hello";


            for (String[][] row: arrays)
             Arrays.fill(row, arraytext);


            for (int a = 0; a<=x; a++){
              for (int b = 0; b<=x; b++){
                  for (int j = 0; j<=i; j++)
                      {System.out.println(arrays[a][b][j]);}

                                    }
                                }

Answer 1

You have a problem filling your array. you are getting

java.lang.ArrayStoreException: java.lang.String at Arrays.fill(row, arraytext);

That is cause you are trying to add a String when is expected an String[][]. And for printing you can use Arrays.deepToString() is your answer.

System.out.println(Arrays.deepToString(arrays));

Example:

public static void main(String[] args) {
        String[][][] array3d = new String[10][10][10];

         for(String [] [] array2d : array3d){
             for(String[] array : array2d){
                 Arrays.fill(array, "hello");
             }
         }

         System.out.println(Arrays.deepToString(array3d));

    }

Answer 2

The problem is that this:

for (String[][] row: arrays)
     Arrays.fill(row, arraytext);

Is trying to pass row , which is a double array of strings, to a function expecting a single array of strings. To get the bottom level of your 3D array, you want this:

for (String[][] slice: arrays)
    for (String[] row: slice)
        Arrays.fill(row, arraytext);

You also have both issues addressed by other answers in your double loop: You'll get an index out of bounds unless you change the <= s to < , and sub isn't defined.

Answer 3

You're going out of bounds on your arrays, instead of <= try < .

for (int a = 0; a < x; a++){
          for (int b = 0; b < x; sub++){
              for (int j = 0; j < i; j++)
                  {System.out.println(arrays[a][b][j]);}

                                }
                            }

Also, what is sub ? You're code snippet should show where you define this variable.

Answer 4

Looks like you are experiencing off by 1 error (use < instead of <= ):

for (int a = 0; a<x; a++){
   for (int b = 0; b<x; b++){
      for (int j = 0; j<i; j++)
      {System.out.println(arrays[a][b][j]);}

   }
}

Since you declared arrays as

String[][][] arrays = new String[x][x][i];

the bounds are from 0 to x-1 for the first two indexes, and 0 to i-1 for the thrid index.

Answer 5

另外，在第二个循环中，您要递增未知变量sub而不是b

Answer 6

You just forgot to replace a temporary value from copy-pastaing

for (int a = 0; a<=x; a++){
    for (int b = 0; b<=x; sub++){ // sub here <---
        for (int j = 0; j<=i; j++) {
            System.out.println(arrays[a][b][j]);
        }
    }
}

Also see @jh314 's answer, your doing the off by one error

Answer 7

package academy.learnprogramming;

import java.util.Arrays;

public class Print3DArray {

public static void main(String[] args) {

    // declare & initialize an int 3D array firstInt3D
    int[][][] firstInt3D = {
            {{1,2}},
            {{3,4}},
            {{5,6,7,8},{9,10}},
            {{11},{12,13,14}},
    };



    // print all values of firstInt3D page by page
    int x = 0;
    for (int[][] accessPage: firstInt3D){
        System.out.println("page:" + x);
        if (x < firstInt3D.length) x++;
        for (int[] accessRow: accessPage){
            System.out.println(Arrays.toString(accessRow));
        }
        System.out.println();
    }
}

}