How to swap rows and columns of a 2d array?

Question

I\'m trying to write a method for \'transpose\' a two-dimensional array of integers, in which the rows and columns of the original matrix are exchanged.

However, I have n

Answer 1

The transpose of a matrix

int m = 4;
int n = 5;

// original matrix
int[][] arr1 = {
        {11, 12, 13, 14, 15},
        {16, 17, 18, 19, 20},
        {21, 22, 23, 24, 25},
        {26, 27, 28, 29, 30}};

// transposed matrix
int[][] arr2 = new int[n][m];

// swap rows and columns
IntStream.range(0, n).forEach(i ->
        IntStream.range(0, m).forEach(j ->
                arr2[i][j] = arr1[j][i]));

---

// output to the markdown table
String matrices = Stream.of(arr1, arr2)
        .map(arr -> Arrays.stream(arr).map(Arrays::toString)
                .collect(Collectors.joining("
")))
        .collect(Collectors.joining("

|

"));

System.out.println("| original matrix | transposed matrix |");
System.out.println("|---|---|");
System.out.println("| 
" + matrices + "
 |");

original matrix	transposed matrix
[11, 12, 13, 14, 15] [16, 17, 18, 19, 20] [21, 22, 23, 24, 25] [26, 27, 28, 29, 30]	[11, 16, 21, 26] [12, 17, 22, 27] [13, 18, 23, 28] [14, 19, 24, 29] [15, 20, 25, 30]

---

^{See also: Printing a snake pattern using an array}