st: Conformability error in creating matrix while cross-tabulating data

["Hugh Colaco" <hmjc66@gmail.com>]

Dear Statalist,

I am trying to get the frequency of certain variables and put it in a
matrix (see code below). I need to cross tabulate each variable
q271-q277 with each variable q256-q260. I then need to add the
frequencies of q256-q258 as one group and q259-q260 as the other
group. Finally, I want to create a 7 x 2 matrix of the results
(q271-q277 will be the 7 rows; and q256-q258 & q259-q260 will be the 2
columns).

I ran the following code, but am getting "conformability error". I
think the problem is that I want a 7 x 2 matrix, but I'm using i =
271/277 rather than i=1/7. If this is the case, can you suggest an
alternative?

P.S. - Right now, I have variables q1-q7. I tried to drop them and
rename q271-q277 as q1-q7 (in case this was the issue), without much
luck.

Thanks,

Hugh


matrix results = J(7,2,.);

forval i = 271/277 {;
	count if q`i'~=. & q256~=.;
     local a = r(N);
     count if q`i'~=. & q257~=.;
     local a = `a' + r(N);
     count if q`i'~=. & q258~=.;
	matrix results[`i',1] = `a' + r(N);

    	
      count if q`i'~=. & q259~=.;
      local b = r(N);
      count if q`i'~=. & q260~=.;
      matrix results[`i',2] = `b' + r(N);

};

matrix colnames results = NP FP;
matrix rownames results = q271 q272 q273 q274 q275 q276 q277;
matrix li results, noheader;
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