hello
see example below
hope it helps
test = (1:30);
test(3:15) = 0; % create some zeroes in the vector
%% main code %%
test = test(:); % makes test always vertical
tol = eps;
ind1 = find(abs(test) <= tol); % zero elements
ind2 = find(abs(test) > tol); % non zero elements
test_str =num2str(test); % convert numerical to string
[m,n] = size(test_str);
for ci = 1:length(ind1) % zero elements
test_str(ind1(ci),:) = [blanks(n-1) 'a'];
end
for ci = 1:length(ind2) % non zero elements
test_str(ind2(ci),:) = [blanks(n-1) 'b'];
end
