# How can I use a string in legend()?

12 views (last 30 days)
Marcel Stucki on 26 Oct 2020 at 14:58
Commented: Ameer Hamza on 26 Oct 2020 at 15:47
I have the following string:
Now I want to use this string to produce a legend to my figure. So I use
and get this:
But I would like to have this,
which I got by using the following command:
Tthis is exactly the string Legend copied into the function legend().
How can I use directly the string Legend, without copying it to the function legend()?
Edit: I forgot the following code sniplet:
p=zeros(2*length(HG),1);
hold on;
for iter2 = 1:length(HG)
p(2*iter2-1)=plot(freq,real(n(:,iter2)), 'color', cc(iter2,:));
p(2*iter2)= plot(freq,imag(n(:,iter2)),'--', 'color', cc(iter2,:));
end
I use the variable p to skip all dotted lines in the legend.

Ameer Hamza on 26 Oct 2020 at 15:05
Why do you want to use the first syntax? It is not supported in MATLAB. The second syntax is the correct MATLAB's way of drawing the legends.
Marcel Stucki on 26 Oct 2020 at 15:18
Because I build the Legend-string and want to use it now. This is how I build it:
values=1:2:(2*length(HG)); %only the solid line should have a legend
Legend1=strcat('[',sprintf('p(%d) ',values),']',',');
Legend2=cell(length(HG),1);
quote=char(39);
for iter3=1:length(HG)
if iter3<length(HG)
Legend2{iter3}=strcat(quote,'HS+HG=', num2str(HS(iter3)),'+',num2str(HG(iter3)),quote,',');
else
Legend2{iter3}=strcat(quote,'HS+HG=', num2str(HS(iter3)),'+',num2str(HG(iter3)),quote);
end
end
Legend3=string(strjoin(Legend2));
Legend=strcat(Legend1,'{',Legend3,'}');
Walter Roberson on 26 Oct 2020 at 15:21

Ameer Hamza on 26 Oct 2020 at 15:27
Although Walter's comment already shows the problems with eval(), in case you still want to use the current method, then the closest you can get is something like this
fig = figure()
hold on
p(1) = plot(rand(1,10))
p(2) = plot(rand(1,10))
Legend_str1 = "[p(1) p(2)]";
Legend_str2 = "{'ABC', 'DEF'}";
legend(eval(Legend_str1), eval(Legend_str2))

Alan Stevens on 26 Oct 2020 at 15:14
You could use
Legend = ['HS+HG = 0.5+5' ;'HS+HG = 1+5'];
legend(Legend)
But make sure there are the same number of characters (including spaces) in both strings.

#### 1 Comment

Ameer Hamza on 26 Oct 2020 at 15:47
Following alternatives does not require that character arrays have equal lengths.
Legend = {'HS+HG=0.5+5';'HS+HG=1+5'};
legend(Legend)
or
Legend = ["HS+HG=0.5+5";"HS+HG=1+5"];
legend(Legend)

R2020b

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