How to add a legend to a figure, but a legend that changes every iteration in a loop ?

I have a "while" loop (while i< tmax ). What i would like to do is to add the element "curve -- i " to the legend every iteration "i". For example if "i" goes from 1 to 3, the legend will be: curve1 curve 2 curve 3. If "i" goes from 1 to 2, the legend will be only: curve1 curve 2. Is it possible to ensure this flexibility in the legend?

Answer 1

[Madhav Rajan]

I understand that you want to add a legend to your figure that changes at every iteration of the loop. You can use the ' drawnow ' function to draw your legend and update your figures. You can refer the example shown below. I have also included a 3 second delay between every iteration to see the legend's string changing from 'curve 1' to 'curve1 curve 2' and so on.

   j = 1;
   prev = '';
   while j < 4

     ph(j) = plot(rand(1,20));
     hold on
     curr = [prev sprintf('curve %d', j)];
     legend(ph(j), curr);
     prev = curr;
     j = j+1
     drawnow; % draw now function
     pause(3); % Added a three second delay to show each iteration, you can modify this.
   end

   hold off

Hope this helps.

[bh dhouha]

This is axactly what i want :) thanks a lot

Answer 2

[Sergio Lobo]

I found this modification to work better:

j = 1;
   leg = {'a', 'b', 'x'};
   figure()
   hold on
   while j < 4
     plot(rand(1,20))
     curr(j) = leg(j) 
     legend( curr);
     j = j+1;
     pause(3);
   end

     hold off

Answer 3

[Walter Roberson]

You can use sprintf() to construct the strings that you legend() . For example,

   i = 0;
   residue = sqrt(2);
   while residue > 0.1
     i = i + 1;
     h(i) = plot(rand(1,20));
     hold on
     legend(h(i), sprintf('curve %d', i));
     residue = residue - rand();
   end

[bh dhouha]

when i ran this code it showed only the legend "crve 3" not all the legend