How to delete an empty matrix ?

i want delete an empty matrix in this code, after running this code you will get an empty matrix...

 a=[   30.4596   37.6811   93.0000
  154.6678  172.8173   91.0000
  44.7308  175.6077   94.0000
  90.8282  191.0239   91.0000
  149.5394  149.1930   70.0000];
b=  [9.0000];
tolerance = 0.00001;
% Subtract third columns
matches = abs(a(:,3) - b) < tolerance
% Extract matching rows.
c = a(matches, :);

now i want to delete this "Empty matrix: 0-by-3", how to delete it.

Answer 1

[per isakson]

Try

    clear a

[Image Analyst]

I think what was meant was

clear c

or

clear('c');

Answer 2

[Image Analyst]

I already showed you how to do it with clear('c') in your duplicate post http://www.mathworks.com/matlabcentral/answers/174121-how-to-compare-different-matrix#comment_263635 - no reason to post the question again. I also said that I don't think it's a good idea because when you later go to check it, it will throw an exception if you had deleted it. If you bail out of the function if it's empty, then that's fine but if you're doing that then there's no reason to delete it at all.

[Matlab111]

ya sorry for that i won't repeat it again sir.. but thank a lot and you helped me a lot, sir...