Remove data elements of the legend from figure

Hi,

I have several figures in a loop-rich script in which the information of the legend would vary for most of the figures. I was wondering if there is a way of removing data elements from the legend using figure setting options. I know I can insert/remove the legent, rename the data points, change the legend appearance, etc, but I am not sure if I can remove elements from it.

For example, in the figure below I would've like to remove the last column but not by using code, instead doing it from the figure itself.

I am aware my changes won't be saved.

Answer 1

[Kelly Kearney]

Technically, you can delete parts of a legend, but I only know how to do it via code, not via to UI.

I should mention that using the multiple-output syntax for legend is "not recommended" by the official documentation, meaning this code could easily break in future versions of Matlab... but they've been saying that since the HG2 release in 2014b and so far I've only encountered problems in a few edge cases.

Anyway, if you really want to delete parts of a legend, here's how you can:

% An example plot, 10 to-be-labeled lines and 3 extras
h1 = plot(rand(10,9), 'ro');
hold on
h2 = plot(rand(10,3), '-k');

lbl = strtrim(cellstr(num2str((1:12)', 'data%d')));

% Label everything
[hleg, hico] = legend(lbl);

% Delete objects associated with last 3 black lines
istxt = strcmp(get(hico, 'type'), 'text');
hicot = hico(istxt);
hicol = hico(~istxt);

delete(hicot(ismember(get(hicot, 'String'), {'data10','data11','data12'})));
delete(hicol(ismember(get(hicol, 'Tag'),    {'data10','data11','data12'})));

The better solution would be to just not label those lines at all from the start:

% An example plot, 10 to-be-labeled lines and 3 extras
h1 = plot(rand(10,9), 'ro');
hold on
h2 = plot(rand(10,3), '-k');

lbl = strtrim(cellstr(num2str((1:12)', 'data%d')));

% Label only the desired lines
legend(h1, lbl(1:9))

[Marisabel Gonzalez]

Thanks Kelly!

[Afiq Azaibi]

Starting in R2024b, calling legend with multiple outputs will throw a warning. It will continue to function as it has previously.

Answer 2

[EL ISMAILI Mohammed]

Hi!

For removing a legend element dirctly from the figure :

-Right click on the legend

-Open "Proprety Inspector"

-Go to: LABELS > Strings. Double clicks on the string's box

-Remove/Edit what you want

It works for me. I have the matlab version 2019a.

[James Ratti]

When I try this, it deletes the legend name, but not the associated color/symbol key for the entries. So if I have 7 entries and want to hide the names/keys for the first 4 of them by modifying the strings, the other 3 just move to the top of the list and become disconnected from the color/symbol keys they're supposed to represent. I can't find a way around this without the command line.

[Narges Raee]

same problem as James! it is deleted the names of the objects and shift eveything else up, so not working!

Answer 3

[Adam Danz]

" I was wondering if there is a way of removing data elements from the figure itself"

If you want to remove objects from a figure that has already been produced, just click on the object and press delete. That will also remove its representation in the legend.

Another option is to selection objects by using the display name in the legend. For example, these lines below will find the handle(s) to the object(s) associated with the legend name "data1" and will delete all of those objects.

allChildren = get(gca, 'Children');                % list of all objects on axes
displayNames = get(allChildren, 'DisplayName');    % list of all legend display names

% Remove object associated with "data1" in legend
delete(allChildren(strcmp(displayNames, 'data1')))

If you want to keep the object on the figure but want to remove its representation from the legend, the only way I know of doing that is to recreate the legend using the object handles to specify legend components. We can get the text in the legend and delete or edit that but we do not have access to the handles of the legend components. Most of the time, the figure can be recreated and that's the much easier approach. But if you've got a figure and no code to reporduce it, you'll have to obtain the handles of all graphic objects and then recreate the legend.

[Marisabel Gonzalez]

Thanks Adam Danz, but I am only interested in removing the data element from the legend. Not from what it's plot in the figure...

[Adam Danz]

" I was wondering if there is a way of removing data elements from the figure itself"

The legend is different from the figure.

I'll edit my answer to address that question.

[Marisabel Gonzalez]

What about removing it from the legend now that I edit the question?

[Adam Danz]

There is no simple way of removing components of a legend from the figure without the code that produced the figure. You can rename them, but removing them isn't possible (without the changing the code and reproducing the figure).

If you have the code that generated the figure, you can edit it so that the legend appears the way you want it to -- that is much simpler.

There's probably a very complicated and error-prone way of getting all axis object handles and associating then trying to associate them with the legend text in order to re-create the legend but if the legend strings were added with calling legend instead of using 'DisplayNames', then this probably wouldn't work either.

[Payam Razavi]

% Thanks for this comment, it was really helpful

% If axes cannot be deleted (invisible axes) use:

legend(app.UIAxes,allChildren(~strcmp(displayNames, '')),'location','Best')

Answer 4

[HiWave]

Although an answer has been accepted, I'm going to add to the discussion. I too faced a similar circumstance. I found the easiest method was to select the data I wanted to keep, then cut. Delete all the rest of the data and legend, then paste the data back into the plot. Add a new legend and rename the entries. Not exactly efficient, but got the job done. No code necessary.

[HiWave]

FYI, if you want to then append extra data, without it appearing in the legend, you can turn off "auto update" in the properties.

[Kaveh Vejdani]

Thank you HiWave! You're right, the ultimate answer is :

L.AutoUpdate = 'off';

Saves the day!

Answer 5

[Peter Beringer]

There's a very simple way if you're happy to do it in the Figure window itself (you can also go File > Generate Code if you wish to include the settings in the code directly). You're correct that editing the text string in the Properties Inspector is going to leave the unwanted data in the legend, just without a name. Easiest way to do it from within the figure is to go to the top of the Property Inspector window, click the ">" arrow next to "Figure" to open up a drop-down menu, then Apple/command-click or right-click the data you don't want and select "DELETE". See attached screenshot (obviously yours will have different labels, etc.) Hope I've explained that okay.

Happy MATLABBING! :)

[SIMONE GRANDINETTI]

I tried this but it deletes the data from the plot as well (i was trying to plot a yline alongside a set of curves but i didn't want it to appear in the legend).