Matlab, barchart and legends

Question

I have a function plot_result()which plots bars from the result on the basis of a test. I have two vectors:

R = [0 1 1 -1] containing logical true or false from the questions. and
T = [0 1 2 3] containing time spent on each questions.

0 - in R means a question not answered

a bar is green if the answer is 1 and red otherwise. But the legends show something else than expected.

in the above case R and T the legend show:

Green - "Right answer"
Green - "Right answer"

instead of

Green - "Right answer"
Red   - "Wrong answer"

sometimes it also shows 3 legends instead of two - what am I doing wrong ?

R = [0 1 1 -1];
T = [0 1 2 3];


if sum(T) ~= 0 

% Barchart
figure;
for i=1:length(T)
    h(i) = bar(i, T(i));
       if i == 1 hold on, end
          if R(i) == -1 
             col = 'r';
             legendInfo{i} = ['Wrong Answer '];
          else
             col = 'g';
             legendInfo{i} = ['Right Answer '];
          end

       set(h(i), 'FaceColor', col)
       end
   end

         set(gca,'xTick',1:length(R),'xTickLabel',1:length(R))
         xlabel('Answer No..');
         ylabel('Time per. question')
         title('Question vs. time')
         set(gca,'YLim',[0 max(T)])

         [~,legendsIWant]=unique(nonzeros(R)); 
         legend(h(legendsIWant),legendInfo(legendsIWant),'Location', 'BestOutside'   'FontSize', 8);

Answer 1

The problem with the given input is [~,legendsIWant]=unique(nonzeros(R)) will give the indexes values corresponding to nonzeros(R) not R

a possible fix would be to get all unique values locations and then discard any corresponding to zero e.g. replace the line mentioned with

[uniqueValues,legendsIWant]=unique(R)
legendsIWant=legendsIWant(uniqueValues~=0)