I have problems with multi legends

Can you give some idea for my problem like this:

for plot legend end

then

if (main)
  if 1
    plot
    legend
  if 2
    plot 
   legend
  ...
  if n
    plot
   legend
  end
end

for each legend I want to renew the legend box and I want to add it to box and I want to update and enlarge the box.

Thanks

Answer 1

[dpb]

First, save the handle to the legend on creation. Then, also save the line handles created by plot each time in an array and augment the handle 'String' property associating the the cell array of titles with the line plot handles...

hL=zeros(N,1);      % for line handles
hL(1)=plot(...;     % first line
lab{1,1}=num2str(1,'Line %2d');  % first label
hLg=legend(lab);    % create the legend object, first label
hold on             % to add onto existing...
for i=2:N           % subsequent after first preparation
  hL(i)=plot(...;   % next line
  lab{i,1}=num2str(i,'Line %2d');  % and next label add to cell array
  legend(hL,lab);   % apply the current labels to the existing line handles..
end

Alternatively, of course, you can build the array of data as a 2D array and wait and plot all in "one swell foop" and then legend can automagically do the association of an array of labels one:one with the lines (columns) in the array. But, the above is the pattern to do it a line at a time which has its reasons for doing so, granted...

[Korhan Cengiz]

thanks your reply but can you send me example with usage of if clauses.

[dpb]

What about if? There are examples at

doc if

The issue you outlined above re: adding to a legend has to do with keeping track of the handles of the objects in the axes to be added to an existing legend, not if...that appears a distraction.