在每行之后打印二维数组中行的总和

Question

我试图在该行之后打印出每一行的总和。需要这样格式化

2 5 6 3| 16
9 4 4 7| 24
1 10 2 3| 16
8 4 5 3| 20
-----------------
20 23 17 16| 76

不必那么好，但接近它。我必须使用 toString 方法，这是我到目前为止所拥有的。 编辑：感谢@KevinAnderson 解决了。需要将 rowSum[r] 附加到数组，而不是尝试使用另一个 for 循环来获取值。

public String toString() {
    //Stores the colSum into a string col
    String col = "";
    for (int j = 0; j < cell[0].length; j++) {
        col += " " + colSum[j];

    }
    //Calculates the total of both the rows and columns
    for (int i = 0; i < cell.length; i++) {
        for (int j = 0; j < cell[0].length; j++) {
            grandTotal += cell[i][j];
        }
    }
    //Prints the array
    String array = "";
    for (int r = 0; r < cell.length; r++) {
        for (int c = 0; c < cell[r].length; c++) {
            array += " " + cell[r][c];
        }
        array += "|" + +rowSum[r] + "\n";
    }
    return array + "-----------------" + "\n" + col + "| " + grandTotal;
}

rowSum 和 colSum 以单独的方法计算，如果需要，可以提供，但它们确实按预期工作。

我认为我需要做的是将 rowSum 的值存储在 int 值中并打印出来，或者以某种方式递增 rowSum。我都试过了，到目前为止它会打印出它存储到的整个数组。

Answer 1

这里是使用两个 for 循环的解决方案。 一个打印行的总和另一个打印列的总和 还要在第一个或第二个 for 循环中构建整个总和。

package so;

import java.util.*;

public class RemoveString {
    public static void main(String[] args) {
        int[][] arr = {{2, 5, 6, 3}, {9, 4, 4, 7}, {1, 10, 2, 3}, {8, 4, 5, 3}};
        System.out.println(toString(arr));
    }

    public static String toString(int[][] cell) {
        int sum = 0;
        int allSum = 0;
        int counter = 0;
        String resultString = "";

        for (int i = 0; i < cell.length; i++) {
            for (int j = 0; j < cell[i].length; j++) {
                // Count the columns for the condition later on
                if (i == 0) {
                    counter++;
                }
                sum += cell[i][j];
                resultString += cell[i][j] + " ";
            }
            resultString += "| " + sum + "\n";
            sum = 0;
        }

        resultString += "--------------\n";

        for (int i = 0; i < counter; i++) {
            for (int j = 0; j < cell.length; j++) {
                sum += cell[j][i];
            }
            allSum += sum;
            resultString += sum + " ";
            sum = 0;
        }

        resultString += "|" + allSum;
        return resultString;
    }
}

创建输出

2 5 6 3 | 16
9 4 4 7 | 24
1 10 2 3 | 16
8 4 5 3 | 20
--------------
20 23 17 16 |76

Answer 2

你可以先用rows和columns准备两个sums数组，这样打印起来比较容易：

 2  5  6  3 | 16
 9  4  4  7 | 24
 1 10  2  3 | 16
 8  4  5  3 | 20
----------------
20 23 17 16 | 76

代码：

// assume that we have a rectangular array
int[][] arr = {
        {2, 5, 6, 3},
        {9, 4, 4, 7},
        {1, 10, 2, 3},
        {8, 4, 5, 3}};

// array of sums by rows
int[] sum1 = Arrays.stream(arr)
        .mapToInt(row -> Arrays.stream(row).sum())
        .toArray();

// array of sums by columns
int[] sum2 = Arrays.stream(arr)
        .reduce((row1, row2) -> IntStream
                .range(0, row1.length)
                .map(i -> row1[i] + row2[i])
                .toArray())
        .orElse(null);

// output
IntStream.range(0, arr.length)
        // iterate over the indices of the rows of an array
        .peek(i -> Arrays.stream(arr[i])
                // elements of the row
                .forEach(e -> System.out.printf("%2d ", e)))
        // sum of the row
        .peek(i -> System.out.printf("| %2d", sum1[i]))
        // end of the row, new line
        .forEach(i -> System.out.println());

// line of hyphens, assume that all numbers are two-digit
System.out.println("-" .repeat(arr[0].length * 2 + arr[0].length + 4));

// line of sums by columns
IntStream.range(0, sum2.length)
        // sum of column
        .forEach(i -> System.out.printf("%2d ", sum2[i]));

// last number, sum of sums, total
System.out.printf("| %2d", Arrays.stream(sum2).sum());

"%2d" - 格式为 两位 数字。

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^{另见：Pascal's triangle 2d array - formatting printed output}