Legend - for plots in if condition

for j = 1:laenge4(1,2)
if isempty(TempVolt(j).data) == true;
else
x_axes = volt_data(:,1);
y_axes = time_data(:,2);
if volt_data(1)== 7
  a1 = plot(x_axes,y_axes,'bs','DisplayName','@7V');     
  hold on;
  end       
if volt_data(1)== 13.5
 a2 = plot(x_axes,y_axes,'gs','DisplayName','@13.5V');
hold on;
end
if volt_data(1)== 18
 a3 = plot(x_axes,y_axes,'ks','DisplayName','@18V');
 hold on;
end
end
end
l = legend('show')
set(l, 'Interpreter','none');

But I want to display all 3 legends even if the plots a2 and a3 are not plotted. Can anyone please help me. Becoz in for loop for other values of 'i' a2 or a3 can be plotted.

Please help me

Answer 1

[Jan]

What about setting the visibility?

for j = 1:laenge4(1,2)
  if ~isempty(TempVolt(j).data)
    x_axes = volt_data(:,1);
    y_axes = time_data(:,2);
    a1 = plot(x_axes,y_axes,'bs','DisplayName','@7V', ...
              'Visible', OnOffStr(volt_data(1) == 7));
    hold on;
    a2 = plot(x_axes,y_axes,'gs','DisplayName','@13.5V', ...
              'Visible', OnOffStr(volt_data(1)== 13.5));
    a3 = plot(x_axes,y_axes,'ks','DisplayName','@18V', ...
              'Visible', OnOffStr(volt_data(1)== 18));
  end
end

function S = OnOffStr(V)
if V
  S = 'on';
else
  S = 'off';
end

Does this works or do invisible line vanish from the legend?

[Meera]

Hello Jan Simon,

I got the following error 'Function definition is misplaced or improperly nested.' can we use the statement 'function' in the middle of the program.?

Thanking you. Meera

[Jan]

Function definitions are allowed inside function M-files, not in scripts and not in the command window. So either create a new file called OnOffStr.m and store it in a user-defined folder inside your Matlab path. Or append teh definition of the function to your function file. If you use a script currently, think of converting it to a function.