Can I manipulate the legend?

The following code will plot me 68 markers. Each marker will have a different color depending on the value of I. Is there a way I can get my legend to show all 5 colors ? For now it is just showing the marker for the first 5 plots, and I just need one per color. If you have any idea or other suggestions that can work as well please let me know.

%for ii=1:1:length(x)
  if I(ii)==0;
    plot(x(ii), y(ii),'bx','LineWidth',2,'MarkerSize',15)  
    hold on %attached flow
  elseif I(ii)==1;
    plot(x(ii), y(ii),'yx','LineWidth',2,'MarkerSize',15)
    hold on %energized
  elseif I(ii)==2;
    plot(x(ii), y(ii),'mx','LineWidth',2,'MarkerSize',15)
    hold on %highly energized
  elseif I(ii)==3;
    plot(x(ii), y(ii), 'rx','LineWidth',2,'MarkerSize',15)
    hold on %seperated
  else 
    plot(x(ii), y(ii), 'x','LineWidth',2,'MarkerSize',15)
    hold on %incipient
  end
%end

Answer 1

[Star Strider]

Try this:

L = 100;
I = randi([0 4], 1, L);
x = randn(1,10);
y = randn(1,10);

figure(1)
hold on
for ii=1:1:length(x)
  if I(ii)==0;
    hl0 = plot(x(ii), y(ii),'bx','LineWidth',2,'MarkerSize',15)  
%     hold on %attached flow
  elseif I(ii)==1;
    hl1 = plot(x(ii), y(ii),'yx','LineWidth',2,'MarkerSize',15)
%     hold on %energized
  elseif I(ii)==2;
    hl2 = plot(x(ii), y(ii),'mx','LineWidth',2,'MarkerSize',15)
%     hold on %highly energized
  elseif I(ii)==3;
    hl3 = plot(x(ii), y(ii), 'rx','LineWidth',2,'MarkerSize',15)
%     hold on %seperated
  else 
    hl4 = plot(x(ii), y(ii), 'x','LineWidth',2,'MarkerSize',15)
%     hold on %incipient
  end
end
hold off
legend([hl0, hl1, hl2, hl3, hl4], 'attached flow', 'energized', 'highly energized', 'seperated', 'incipient')

[Coral Reyes]

it didn't work . It says

Undefined function or variable 'hl1'

[Star Strider]

That simply means that there were no values of I(ii) that were equal to 1. It works if there are — I tested it to be sure.

I don’t have your data, so I can only simulate them and test your code against my simulations.