在Java中显示二维数组

Question

I have an x by y board of numbers stored in a two dimensional array in java that I would like to print out to the user in a nice formatted manner. Would there be an easy way to do this in java?

Here is how I build my board:

board = new int[TotRow][TotCol];

Answer 1

If you want the number to be padded properly as well use String.format() ,

for (int i = 0; i < TotRow; i++) {
    for (int j = 0; j < TotCol; j++) {
        System.out.print(String.format("%3d", board[i][j]) + "\t");
    }
    System.out.println();
}

Notice that I have used %3d for formatting, you can use format as required by you

Answer 2

for (int i = 0; i < x; i++) {
    for (int j = 0; j < y; j++) {
        System.out.print(board[i][j] + "\t");
    }
    System.out.println();
}

Answer 3

You can print the board two dimensional array like this

for (int i = 0; i < board.length; i++) {
    for (int j = 0; j < board[i].length; j++) {
        System.out.print(board[i][j] + "\t");
    }
    System.out.println();
}

Answer 4

You might prefer the one line, because it's easy, Arrays.deepToString(Object[]) the Javadoc says (in part),

This method is designed for converting multidimensional arrays to strings.

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

Answer 5

Since I don't like relying on tabs, I'd like to mention some approaches that don't rely on them.

If you know that all of the numbers in the table are nonnegative numbers of, say, 4 digits or less, you can use String.format in a manner similar to Nitin's answer:

for (int i = 0; i < TotRow; i++) {
    for (int j = 0; j < TotCol; j++) {
        System.out.print(String.format("%4d ", board[i][j]));
    }
    System.out.println();
}

The %4d means to format the number using a width of 4 characters, and pad with blanks on the left if the number takes fewer than 4 characters to print. Thus, if there aren't any 5-digit or longer numbers, each print will print exactly 5 characters--a 4-character field for the number, and a space after the number. This will make everything line up, as long as none of the numbers is too large. If you do get a number that takes more than 4 characters, the formatting will get messed up.

Here's a way to adjust the column width so that it's just large enough to hold all the values in the table, and works fine if there are negative numbers:

int maxWidth = 0;
for (int i = 0; i < TotRow; i++) {
    for (int j = 0; j < TotCol; j++) {
        maxWidth = Math.max(maxWidth, Integer.toString(board[i][j]).length());
    }
}
String format = "%" + maxWidth + "d ";
for (int i = 0; i < TotRow; i++) {
    for (int j = 0; j < TotCol; j++) {
        System.out.print(String.format(format, board[i][j]));
    }
    System.out.println();
}

not tested

Answer 6

You basically just use a nested loop.

for (int i = 0; i < board.length; i++) {
    for (int j = 0; j < board[i].length; j++) {
        System.out.print(board[i][j] + " ");
    }
    System.out.println();
}