How can I base my legend on the markers I defined in my plot?

I have a large data set form wich I want to plot quite some graphs, 105 to be exacly. In these graphs a maximum of 4 lines is plotted but not in every graph. I have added a maker and a line color so that they are easy to diffentiate for eachother. I want to add a legend to these so that you can see which line is what. The legend however get, I think, overruled when a new line is added and if I add the legend at the end of my code it wil not refer to te right line if not all the 4 lines are in the graph. Is it possible to create a legend based on the linecolor of on the marker?

 if Config_num(a,1) ~= Configuration(c-1,1) && Config_num(a,1) == Configuration(c,1) 
           n= sum(Configuration == Config_num(a,1)); 
           plot(Fn(c:c+n-1,1),Rel_rest(c:c+n-1,1),'-bo')
           T = {'Lp/Bpx ='  LpBpx(c,1) , 'Ap/\Nabla ='  ApNabla23Rounded(c,1) ,  'LCG ='  LCG(c,1)};
           legend('\beta = 12.5', 'Location', 'northwest');
           title(T)
        
        elseif Config_num(a,2) ~= Configuration(c-1,1) && Config_num(a,2) == Configuration(c,1)
               n= sum(Configuration == Config_num(a,2));
               plot(Fn(c:c+n-1,1),Rel_rest(c:c+n-1,1),'-rx')
               legend('\beta = 19', 'Location', 'northwest');
               title(T)
       
        elseif Config_num(a,3) ~= Configuration(c-1,1) && Config_num(a,3) == Configuration(c,1)
               n= sum(Configuration == Config_num(a,3));
               plot(Fn(c:c+n-1,1),Rel_rest(c:c+n-1,1),'-cs') 
               legend('\beta = 25', 'Location', 'northwest');
               title(T)
               
        elseif Config_num(a,4) ~= Configuration(c-1,1) && Config_num(a,4) == Configuration(c,1)
               n= sum(Configuration == Config_num(a,4));
               plot(Fn(c:c+n-1,1),Rel_rest(c:c+n-1,1),'-m^')
               legend ('\beta = 30', 'Location', 'northwest');
               title(T)
        end

Answer 1

[Rik]

The best solution is to set the DisplayName property when calling plot, and/or use an array of handles to create the legend. See the examples below.

x=linspace(0,10,50);
y1=5*cos(x)+rand(size(x));
y2=4*sin(x)+rand(size(x));
y1a=y1+0.5*rand(size(x));
y1b=y1-0.5*rand(size(x));
figure(1),clf(1)%only use clf during debugging

%example 1:
subplot(1,3,1)
plot(x,y1,'DisplayName','foo'),hold on
plot(x,y2,'DisplayName','bar'),hold off
legend

%example 2:
subplot(1,3,2)
h1=plot(x,y1);hold on
h2=plot(x,y2);hold off
legend([h1 h2],{'foo','bar'})

%example 3:
subplot(1,3,3)
h1=plot([x;x]',[y1a;y1b]');hold on
h2=plot(x,y2);hold off
legend([h1(1) h2(1)],{'foo','bar'})