Legend in for loop

Good evening

In the following code, I am having 8 plots at the end, for one distance value I have two plots. One for LoS path, the other for NLoS path.But all in one figure. I tried to put a legend but it gives me an error. What is the correct syntax to do it?

thank you

 for k=1:length(R)
     [HL,HN] = Channel_LoS(p,R(k),dt(k),dr(k));
     plot(p.f,HL)
     hold on
     plot(p.f,HN)
 end 
hold off

Answer 1

[Adam Danz]

What code did you use to produce your legend and what was the error? Do you want a legend for each subplot or 1 legend for the whole figure? There's lots of ways to go about this depending on what you're looking for. Here's a general solution that can be adapted to your needs.

   for k=1:length(R)
       [HL,HN] = Channel_LoS(p,R(k),dt(k),dr(k));
       p1 = plot(p.f,HL);
       hold on
       p2 = plot(p.f,HN); 
   end 
   legend([p1,p2], {'HL', 'HN'})
   hold off

Another solution I often prefer is using the 'DisplayName' property.

   for k=1:length(R)
       [HL,HN] = Channel_LoS(p,R(k),dt(k),dr(k));
       p1 = plot(p.f,HL, 'DisplayName', 'HL');
       hold on
       p2 = plot(p.f,HN, 'DisplayName', 'HN'); 
   end 
   legend([p1,p2])
   hold off

[Alice Faisal]

I tried this

    for k=1:length(R)
     [HL,HN] = Channel_LoS(p,R(k),dt(k),dr(k));
     p1=plot(p.f,HL);
     hold on
     p2=plot(p.f,HN);
     legendInfo{k} = ['LoS, d=' R(k) , 'NLoS, d=' R(k)];
 end 
 legend(legendInfo)
 hold off

but it is not displaying R(n), the numbers in the legend

[Adam Danz]

If R is a numerical vector, it will not appear in legendInfo unless you convert it to a character vector or string. Try something like this:

legendInfo{k} = sprintf('LoS, d=%d, NLoS, d=%d', R(k), R(k));

That assumes R(k) is an integer. If R(k) contains decimals, instead of %d, use %.2f (or whatever precision you want).

[Alice Faisal]

I don't think its right. I think this way will just list them as you wrote without connecting them to the actual curve. This is what I understood from debugging the plot.

[Adam Danz]

Your line of code

legendInfo{k} = ['LoS, d=' R(k) , 'NLoS, d=' R(k)];

is incorrect because the numerical values are not converted to strings.

My line of code

legendInfo{k} = sprintf('LoS, d=%d, NLoS, d=%d', R(k), R(k));

correctly converts the numerical values to strings. However, you still need to use the plot handles to correctly pair the plot elements with the legend text. Look at my answer again and you'll see how I use the plot handles in the legend. You can also play around with the sprintf command to suit your needs. Let me know if you have any follow-up questions.