How to initialize two-dimensional arrays in Fortran

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You can do that using reshape and shape intrinsics. Something like:

INTEGER, DIMENSION(3, 3) :: array
array = reshape((/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), shape(array))

But remember the column-major order. The array will be 

1   4   7
2   5   8
3   6   9

after reshaping.

So to get: 

1   2   3
4   5   6
7   8   9

you also need transpose intrinsic:

array = transpose(reshape((/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), shape(array)))

For more general example (allocatable 2D array with different dimensions), one needs size intrinsic:

PROGRAM main

  IMPLICIT NONE

  INTEGER, DIMENSION(:, :), ALLOCATABLE :: array

  ALLOCATE (array(2, 3))

  array = transpose(reshape((/ 1, 2, 3, 4, 5, 6 /),                            &
    (/ size(array, 2), size(array, 1) /)))

  DEALLOCATE (array)

END PROGRAM main

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