Merging different legend labels

Hello everyone, I haven't spend much time coding in Matlab so this one might be a little silly question. Similar questions have been asked as far as I can see; but none of the solutions provided worked for me. So here I am asking: As can be seen in the attached code and image, I have a graph consisting of five lines, two of them representing the resulst of the first model (green ones) and the rest representing the second model (blue ones). Could not find a way to add legend label for different colours in editor. When I code and graph without legends and insert legend in the figure window, it happens to be that, as expected, there are five different labels for each line. I want to merge the green and blue ones and I am pretty sure it is possible and it is just me who cannot do it. Also in the future 8 more model results will be added, each of them consisting of one, two or three lines. How can I merge the legend labels?

Thanks in advance!

x1 = [1, 2 ,3, 4, 5];
y1 = [5, 3, 2.8, 1.7, 1.2];
y2 = [6.5, 4.7, 3.5, 1.9, 1.3];
x2 = [1, 2, 3, 4, 5];
y3 = [6, 5.6, 3.1, 2.9, 1.7];
y4 = [5, 4.1, 3.8, 2, 1.5];
y5 = [5, 4, 3, 1.8, 1.4];
plot(x1,y1,x1,y2,'color', 'g'); %Model 1
hold on
plot(x2,y3,x2,y4,x2,y5,'color', 'b'); %Model 2
hold off
grid minor
xlabel('x values')
ylabel('y values')
title('figure 1')

[Mahmut Cenk]

Endless thanks to everyone answered. All three suggestions work really well. Thank you guys.

Answer 1

[VINAYAK LUHA]

Hi Mahmut,

My understanding is that you have multiple line plots from different models and want to create a common legend for all line plots from a single model.

You can achieve this by using the "graphics object handles" of the plots along with the MATLAB "legend" function.

Here is a code snippet for your reference:

x1 = [1, 2 ,3, 4, 5];
y1 = [5, 3, 2.8, 1.7, 1.2];
y2 = [6.5, 4.7, 3.5, 1.9, 1.3];
x2 = [1, 2, 3, 4, 5];
y3 = [6, 5.6, 3.1, 2.9, 1.7];
y4 = [5, 4.1, 3.8, 2, 1.5];
y5 = [5, 4, 3, 1.8, 1.4];
 
hold on; 

% Plot Model 1
h1 = plot(x1, y1, 'color', 'g'); 
plot(x1, y2, 'color', 'g'); 
 
% Plot Model 2
h2 = plot(x2, y3, 'color', 'b'); 
plot(x2, y4, 'color', 'b'); 
plot(x2, y5, 'color', 'b');
 
% Add grid, labels, and title
grid minor;
xlabel('x values');
ylabel('y values');
title('Figure 1');
 
% Add legend
legend([h1, h2], {'Model 1', 'Model 2'});
 
hold off; 

For more details on the MATLAB "legend" and "Graphics Object handle", you can refer to the following documentations:

• https://www.mathworks.com/help/matlab/ref/legend.html
• https://www.mathworks.com/help/matlab/creating_plots/how-to-work-with-graphics-objects.html

Hope this answers your question

Regards,

Vinayak

Answer 2

[Matt J]

One way,

x1 = [1, 2 ,3, 4, 5];
y1 = [5, 3, 2.8, 1.7, 1.2];
y2 = [6.5, 4.7, 3.5, 1.9, 1.3];
x2 = [1, 2, 3, 4, 5];
y3 = [6, 5.6, 3.1, 2.9, 1.7];
y4 = [5, 4.1, 3.8, 2, 1.5];
y5 = [5, 4, 3, 1.8, 1.4];
Model1=plot(x1,y1,x1,y2,'color', 'g'); %Model 1
hold on
Model2=plot(x2,y3,x2,y4,x2,y5,'color', 'b'); %Model 2
hold off
grid minor
xlabel('x values')
ylabel('y values')
title('figure 1')

legend([Model1(1), Model2(1)],'Model 1','Model 2')

Answer 3

[Catalytic]

x1 = [1, 2 ,3, 4, 5];
y1 = [5, 3, 2.8, 1.7, 1.2];
y2 = [6.5, 4.7, 3.5, 1.9, 1.3];
x2 = [1, 2, 3, 4, 5];
y3 = [6, 5.6, 3.1, 2.9, 1.7];
y4 = [5, 4.1, 3.8, 2, 1.5];
y5 = [5, 4, 3, 1.8, 1.4];

X1=[x1 nan x1]; Y1=[y1 nan y2];
X2=[x2 nan x2 nan x2]; Y2=[y3 nan y4 nan y5];

plot(X1,Y1,'g', X2,Y2,'b');  legend 'Model 1' 'Model 2'

grid minor
xlabel('x values')
ylabel('y values')
title('figure 1')