如何获得二维数组中的最小值

Question

I need help, please! I am building up the following code to extract the minimum value of each column of the distance

I have tried to compute the code but to no avail

public static void main(String[] args) {
    int data[] = {2, 4, -10, 12, 3, 20, 30, 11};//,25,17,23};    // initial data
    int noofclusters = 3;
    int centroid[][] = new int[][]{
            {0, 0, 0},
            {2, 4, 30}
    };
    getCentroid(data, noofclusters, centroid);
}

public static int[][] getCentroid(int[] data, int noofclusters, int[][] centroid) {

    int distance[][] = new int[noofclusters][data.length];
    int cluster[] = new int[data.length];
    int clusternodecount[] = new int[noofclusters];


    centroid[0] = centroid[1];
    centroid[1] = new int[]{0, 0, 0};
    System.out.println("========== Starting to get new centroid =========");

    for (int i = 0; i < noofclusters; i++) {
        for (int j = 0; j < data.length; j++) {
            //System.out.println(distance[i][j]+"("+i+","+j+")="+data[j]+"("+j+")-"+centroid[0][i]+"="+(data[j]-centroid[0][i]));
            distance[i][j] = Math.abs(data[j] - centroid[0][i]);
            System.out.print(distance[i][j] + " ,");
        }
        System.out.println();
    }

    int[] result = new int[distance.length];
        for (int i = 0; i < distance.length; i++) {
            //int min = distance;
            int min = distance[i][0];
            for (int j = 0; j < distance[0].length; j++) {

                if (distance[i][j] < min) {
                    min = distance[i][j];
                }

                result[j] = min;
                System.out.println(result[j] + ", ");
            }

        }
        return result;
    }
}

The result of the computation for distance gives

 row 1: 0 ,2 ,12 ,10, 1 ,18 ,28 ,9 row 2: 2 ,0 ,14 ,8 , 1 ,16 ,26 ,7 row 3: 28,26,40 ,18, 27 ,10 ,0 ,19 

I want to go through each column to get the minimum value

0 0 12 8 1 10 0 7

Thanks for your help in advance

Answer 1

To get the minimum value in each column, first, you need to iterate the column in the outer loop. By doing so, we can access the matrix colunm-wise.

Assign the first value of each column to a variable. Then iterate through the rows in the inner loop.

Check if the current value is less than the minimum value. If so, assign the smallest value to minimum.

When we use an array, we get an array of minimum values of the column.

To obtain the minimun value in each row, swap the loops and use min[i] .

Below is an example code:

int []min = new int[column_lenght];
for(int j = 0; j < column_length; j++) {
    min[j] = array[i][j];
    for(int i = 0; i < row_length; i++) {
        if(array[i][j] < min[j]) {
            min[j] = array[i][j];
        }
    }
}

The min[] will contain the minimum value of each column.