如何将二维数组展平为一维数组

Question

How would i transfer a 2d array into a 1d array in java. I have the code for the 2d array but dont know where to start. The output of the 2d array is a 8 by 10 grid with the numbers going from 1-80.

public class move
{
    public static void main (String[] args)
    {

        int[][] twoarray = new int[8][10];

        int i ;
        int j ;

        for(i =0; i < 8; i++)
        {
            for(j = 0; j < 10; j++)
            twoarray[i][j] = (i * 10 + j+1);
        }


        for(i = 0; i < 8; i++)
        {
            for(j = 0; j < 10; j++)
            {
                System.out.print(twoarray[i][j]);
                System.out.print("  ");


            }
            System.out.println();
        }

        int[] array = new int[80];

    }
}

Answer 1

Using Java 8

int[] array = Stream.of(twoarray)
                    .flatMapToInt(IntStream::of)
                    .toArray();

Using Java 7 or older

int[] array = new int[80];
int index = 0;
for (int[] row : twoarray) {
    for (int val : row)
        array[index++] = val;
}

Answer 2

You can do in your for loop:

int[] array = new int[80];
int k=0;
for(i = 0; i < 8; i++){
    for(j = 0; j < 10; j++){
        array[k++]=twoarray[i][j];
    }
}