多维数组列交换

Question

After identifying that elements in a specific column of a multidimensional array are not numbers I'm looking at swapping two columns of this multidimensional array.

Basically I would like to swap the contents of column 4 with those in column 6 after determining whether elements in column 6 are numbers or not so if elements in column 6 are not numbers then create new array and start inserting old array contents in new array but once the column gets to the 4th column of the old array it places this element in the 6th column of the new array and vice versa.

Below is my attempt regarding the above. I've been able to successfully identify if the elements in my column 6 are numbers or not. I now have doubts regarding the logic behind swapping the elements in column 4 with those in 6.

//!<
public String[][] sortedByDateUsageStatsData(String[][] unsortedUsageStatsData) {
    System.out.println("\nbtnUsageStats - sortedByDateUsageStatsData(String[][] unsortedUsageStatsData)");

    for (int row = 0; row < unsortedUsageStatsData.length; row++) {
        for (int col = 0; col < 7; col++) {
            //System.out.println("unsortedUsageStatsData[" + row + "][" + col + "] => " + unsortedUsageStatsData[row][col]);
        }

        // Check if content in return code column i.e. column 6 is number or a string.
        // If a string then swap column 4 content with column 6 and pass this array with swapped columns as the final array
        if(!isNumericString(unsortedUsageStatsData[0][6])) {
            //System.out.println("unsortedUsageStatsData[0][6] is NOT a number i.e. " + unsortedUsageStatsData[0][6]);

            break;
        }

        System.out.println("\n");
    }

    System.out.println("\nExited for loop as unsortedUsageStatsData[0][6] is NOT a number\n");

    sortedUsageStatsData = new String[unsortedUsageStatsData.length][7];

    for (int row = 0; row < unsortedUsageStatsData.length; row++) {
        for (int col = 0; col < 7; col++) {
            //System.out.println("\nBefore swap unsortedUsageStatsData[" + row + "][" + col + "] => " + unsortedUsageStatsData[row][col]);

            sortedUsageStatsData[row][col] = unsortedUsageStatsData[row][col];

            if(col == 4) {
                System.out.println("\nBefore swap sortedUsageStatsData[" + row + "][6] => " + unsortedUsageStatsData[row][6]);                      
                sortedUsageStatsData[row][6] = unsortedUsageStatsData[row][4];
                System.out.println("\nAfter swap sortedUsageStatsData[" + row + "][6] => " + unsortedUsageStatsData[row][6]);                       

                sortedUsageStatsData[row][4] = unsortedUsageStatsData[row][6];
                System.out.println("\nAfter swap sortedUsageStatsData[" + row + "][4] => " + unsortedUsageStatsData[row][4]);                       
            }

            System.out.println("\nAfter swap sortedUsageStatsData[" + row + "][" + col + "] => " + unsortedUsageStatsData[row][col]);
        }

        System.out.println("\n");

    }

    return sortedUsageStatsData;
}

Any help is appreciated.

Answer 1

There's a problem with your loop. In the iteration where col == 6 you override the value of sortedUsageStatsData[row][6] you had already set before (when col was 4).

There are a few ways to change this, I'll name two:

1. Iterate from 0 to 5 only: for (int col = 0; col < 6; col++) .

2. Set values of columns 4 and 6 in corresponding iterations:

     if(col == 4) { sortedUsageStatsData[row][4] = unsortedUsageStatsData[row][6]; } else if (col == 6) { sortedUsageStatsData[row][6] = unsortedUsageStatsData[row][4]; }