You can try this code with Java 9 (this causes a compilation error in Java 8, so be careful):
int[][] array = Stream.iterate(1, i -> i < 10, i -> i + 1).collect(() -> new int[3][3], (a, i) -> a[(i - 1) / 3][(i - 1) % 3] = i, (a, i) -> {}); Stream.of(array).forEach(a -> System.out.println(Arrays.toString(a)));
Here is the result:
[1, 2, 3] [4, 5, 6] [7, 8, 9]
With Java 8:
int[][] array = IntStream.range(1, 10).collect(() -> new int[3][3], (a, i) -> a[(i - 1) / 3][(i - 1) % 3] = i, (a, i) -> {}); Stream.of(array).forEach(a -> System.out.println(Arrays.toString(a)));
Here is another solution that supports numbers other than the predefined sequence (1,2,3,4,5,6,7,8,9), but is not as clean as the solution because it uses an array counter:
int[] counter = {0}; int[][] array = Stream.of(4, 2, 3, 4, 5, 8, 9, 8, 11).collect(() -> new int[3][3], (a, i) -> { a[counter[0] / 3][counter[0] % 3] = i; counter[0]++; }, (a, i) -> {});
Output:
[4, 2, 3] [4, 5, 8] [9, 8, 11]
If you want a more universal solution based on the solution above, you can try this piece of code that allows you to set a variable number of columns:
List<Integer> list = Arrays.asList(4, 2, 3, 4, 5, 8, 9, 8, 11, 12, 13, 17, 32, 45, 89, 91, 91, 98, 87); int[] counter = {0}; int cols = 5; int rows = (int) Math.ceil(list.size() / cols) + 1; int[][] array = list.stream().collect(() -> new int[rows][cols], (a, i) -> a[counter[0] / cols][counter[0]++ % cols] = i, (a, i) -> {}); Stream.of(array).forEach(a -> System.out.println(Arrays.toString(a)));
The imprint over the inscriptions:
[4, 2, 3, 4, 5] [8, 9, 8, 11, 12] [13, 17, 32, 45, 89] [91, 91, 98, 87, 0]