MODULE char_test CONTAINS SUBROUTINE change_strings(strings, n_strs, out_strings) IMPLICIT NONE ! Inputs INTEGER, INTENT(IN) :: n_strs CHARACTER, INTENT(IN), DIMENSION(2,n_strs) :: strings CHARACTER, INTENT(OUT), DIMENSION(2,n_strs) :: out_strings !f2py INTEGER, INTENT(IN) :: n_strs !f2py CHARACTER, INTENT(IN), DIMENSION(2,n_strs) :: strings !f2py CHARACTER, INTENT(OUT), DIMENSION(2,n_strs) :: strings ! Misc. INTEGER*4 :: j DO j=1, n_strs out_strings(1,j) = strings(1,j) out_strings(2,j) = 'A' END DO END SUBROUTINE change_strings END MODULE char_test