How can I hold the previous "legend" on a plot?

I use the "hold" function to hold the previous plots. But how can I hold the previous legends, too?

Answer 1

[sadel]

here is the answer that I was looking for:

x=0:.01:10;
plot(x, sin(x), 'DisplayName','sin');
legend('-DynamicLegend');

hold all;   % add new plot lines on top of previous ones
  plot(x, cos(x), 'DisplayName','cos');

[Wycliff Dembe]

This got the job done. Thanks

[Walter Roberson]

In sufficiently new MATLAB, if you called legend without passing in a list of graphics objects, then MATLAB will automatically add new objects created after that point to the legend. Occasionally you may need to

legend show

But back when the question was originally asked, the method shown here was best.

[Michael Sonnenberg]

Thanks for the question and answer.

[Paul Gwambe]

Thank you, it worked for me.

[Harshia Mathur]

worked for me as well, Do you know anyway to customise this? I want to append a string, otherwise all it's saying is data1 , data2 etc..

[Walter Roberson]

@Harshia Mathur example

x=0:.01:10;
for alpha = [1 5 9]
   plot(x, nthroot(sin(x).^alpha,7), 'DisplayName', "sin^{" + (alpha/7) + "}");
   hold on;
end
hold off
ylim auto
legend show

Answer 2

[Gerd]

For example I you would like to show the sin and cos you would use

t=[0:0.1:10]
x=sin(t)
y=cos(t)
plot(t,x)
hold
plot(t,y,'r')
legend('sin','cos')

In your case you have to build the legendstring with the two different "strings" you want to show.

Answer 3

[Gerd]

Hi sadel, to get the current legend use

% you have to have a legend on the current plot
get(legend(gca),'String'); % get legend from current axes.
% Now you can set the legend of the new plot

Gerd

[sadel]

Hi Gerd and thank you for your reply!

My code is on a button and is something like this:

if get(handles.holdaxes,'value')==1

hold on

get(legend(gca),'String');

else

hold off

end

switch get(val1)

case 1

string='vvsdv'

plot 1

legend(string)

case 2

string='vdsvsdvs'

plot 2

legend(string)

end

when I click the button for second time, my program just change the string of the legend but I want to have 2 lines legend. How can I do this?

[Gerd]

Hi sadel, what do you mean by having a 2 lines legend?

Do you want to have 2 plots with 2 legend?

Gerd

[sadel]

yes

[Rajani Metri]

Hello,

but legend holding only text. It is showing legend indicators as lines, instead of asteric lines, which I used. It is not holding the marking points of plots. For holding Marker points of respective plots, what to do?

Thank You.

[Walter Roberson]

Which MATLAB version are you using? And please explain what you are trying to do in more detail?

Answer 4

[Andrea Cavallini]

Quick and dirty... at last (before hold off), draw something out of the scope of the plot, but with the right legend symbols. That will do