legend entries ignored after using "hold" to create plots

I created a yy plot using "hold on" because my data sets were different lengths. Since then, the legend function only recognizes 4 of the 6 data sets plotted so when I add the legend it is incomplete. Can anyone tell me how to get the other entries to show up or maybe there is a better way to plot data sets with different lengths than using the "hold" function.

Thanks!

Answer 1

[Glenn]

Ultimately, I handled this issue by giving up on the yy plot and did a subplot instead. I, nor a couple colleagues, was not able to get the legend to display all entries for the yyplot.

Answer 2

[Thomas]

You could concatenate multiple legend statements for the two data sets

Eg.:

x = 1900:10:1990; x=x'
y1 = 10:10:100; y1=y1'
y2 = -0.1:-0.1:-1; y2=y2'
y3 = 0.05:0.05:0.5; y3=y3'
[AX,H1,H2] = plotyy(x,y1,x,[y2,y3],'plot','plot');
legend(H1,'y1');
legend(H2,'y2','y3');

this will give you only the last legend on the plot

x = 1900:10:1990; x=x'
y1 = 10:10:100; y1=y1'
y2 = -0.1:-0.1:-1; y2=y2'
y3 = 0.05:0.05:0.5; y3=y3'
[AX,H1,H2] = plotyy(x,y1,x,[y2,y3],'plot','plot');

legend([H1;H2],'y1','y2','y3');

this will give the entire data set with legend

[Glenn]

The trouble that I have is that if I cannot use the second method which shows all legend entries because my data sets are different lengths and I have more than 2 (i.e. "x" and "y" have different lengths for each iteration of the loop in which I'm calling them).

maybe seeing the actual code is helpful. The Power_XXX matricies need different lengths for each plotted curve which are dictated by the indices in "ind_DCmax"

figure(2)
%[AX,H1,H2]=plotyy(Power_final,Power_all,Power_final,[100*polyval(P,Power_AC);100*(Power_final/Power_burneroutput);
for i=1:length(T_cold)
    Eff.Power_AC(:,i)=[100*polyval(P(:,i),Power_AC)];
    Eff.System(:,i)=100*(Power_final'./Power_chemical(:,i))
end

Eff.all=[Eff.Power_AC,Eff.System];
%[AX,H1,H2]=plotyy(Power_final,Power_all,Power_final,Eff.all);
for i=1:length(T_cold)
    [AX,H1,H2]=plotyy(Power_final(1:ind_DCmax(i)),Power_chemical(1:ind_DCmax(i),i),Power_final(1:ind_DCmax(i)),Eff.System(1:ind_DCmax(i),i));
    %plot(Power_final(1:ind_DCmax(i)),Power_chemical(1:ind_DCmax(i),i),PropVal1{i},Power_final(1:ind_DCmax(i)),Power_burneroutput(1:ind_DCmax(i),i),PropVal2{i});
    set(AX(1),'ylim',[0 400]);
    set(AX(1),'LineStyle','-','Ytick',[0:50:400]);
    set(AX(2),'ylim',[4 20]);
    set(AX(2),'LineStyle','--','Ytick',[4:2:20]);
    set(H1,'LineStyle','-','LineWidth',2);
    set(H1,'Color',PropVal1{i}(1:1));
    set(H2,'LineStyle','--','LineWidth',2);
    set(H2,'Color',PropVal2{i}(1:1));
    set(get(AX(2),'Ylabel'),'String','Efficiency, %');
    legend([H1;H2],{sprintf('Chemical Input @T_c_o_l_d=%g°C ',T_cold(i)),sprintf('System Efficiency @T_c_o_l_d=%g°C ',T_cold(i))});
    hold on
end
legend(legendtext,'Location','NorthWest');

Thank you for the help!