Legend for selective plot

Hello everyone,

I want legend to automatically update based on what was selcted to plot. I want only vectors that are plotted to be indicated within the legend. How do i do that help!

%first column is the counter ID number, and remaining vector are values the counter counted.
my_mat = [11 2 4 5 6; 
          14 4 5 6 7; 
          25 2 3 4 5;
          56 0 9 8 6]

my_mat = 4×5

11 2 4 5 6 14 4 5 6 7 25 2 3 4 5 56 0 9 8 6

counts = size(my_mat,1);
% Plot only if the the counter ID is amongst the values specified in the if-elseif-else criterion.

for u = 1: size(my_mat,1)
    d = my_mat(u);
    hold on
    if d == 11 
        plot(1:counts, my_mat(u, 2:end),"LineWidth",1,"Color",'r', "LineStyle","-")
    elseif d == 14
        plot(1:counts, my_mat(u, 2:end),"LineWidth",1,"Color",'r', "LineStyle","--")
    elseif d == 34 % not an error. Counter 25 not in criteria, therefore wont be plotted
        plot(1:counts, my_mat(u, 2:end),"LineWidth",1,"Color",'b', "LineStyle","-")
    elseif d == 56
        plot(1:counts, my_mat(u, 2:end),"LineWidth",1,"Color",'b', "LineStyle","--")
    end
    
end

legend('11','14','60','56', "Location","southeast") % As seen , the legend is not 'linked' to what is actually plotted. Its hardwired therefore errorprone as shown. I want only vectors that are actually plotted to be indicated within the legend. help!

Warning: Ignoring extra legend entries.

Thank you for your time.

Answer 1

[Cris LaPierre]

Use the 'DisplayName' property.

%first column is the counter ID number, and remaining vector are values the counter counted.
my_mat = [11 2 4 5 6; 
          14 4 5 6 7; 
          25 2 3 4 5;
          56 0 9 8 6];
counts = size(my_mat,1);
% Plot only if the the counter ID is amongst the values specified in the if-elseif-else criterion.
for u = 1: size(my_mat,1)
    d = my_mat(u);
    hold on
    if d == 11 
        plot(1:counts, my_mat(u, 2:end),"LineWidth",1,"Color",'r', "LineStyle","-",'DisplayName','11')
    elseif d == 14
        plot(1:counts, my_mat(u, 2:end),"LineWidth",1,"Color",'r', "LineStyle","--",'DisplayName','14')
    elseif d == 34 % not an error. Counter 25 not in criteria, therefore wont be plotted
        plot(1:counts, my_mat(u, 2:end),"LineWidth",1,"Color",'b', "LineStyle","-",'DisplayName','34')
    elseif d == 56
        plot(1:counts, my_mat(u, 2:end),"LineWidth",1,"Color",'b', "LineStyle","--",'DisplayName','56')
    end
    
end
legend("Location","southeast")

[klb]

That works. Thank you!