turning a matrix into row vector

[rhapsody]

I have an arrays like this

data prob_matrix;

set B_estimates;

　

array theta theta1-theta9;

end;

 Where theta1 to theta9 are 9 columns from a 9by9 matrix. Now I want to convert the Array theta into a long row. The resulting row vector is then 9*9=81 cells wide, since row 1,2 3 etc from theta are put next to eachother

[RW9]

Well, I would advise that that is not the best layout, going the other way would be more beneficial, i.e. having 81 records and 2 columns.  Far easier to work with.  Anyways something like - and note that this is not tested as you have not provided test data in the form of a datastep.

data want (drop=i);
  set have end=last;
  array final{81} 8;
  retain final:;
  array theta{9};
  if _n_=1 then mult=0;
  do i=1 to 9;
    final{(mult*9)+i}=theta{i};
  end;
  if last then output;
run;