%!demo
%! ## `countcats` tallies how many elements fall in each category, in category
%! ## order.  Categories with no elements are counted as zero, so the result lines
%! ## up one-to-one with `categories`.
%!
%! C = categorical ({'M'; 'S'; 'L'; 'M'; 'S'; 'M'}, {'S', 'M', 'L', 'XL'})
%! categories (C)
%! countcats (C)
