How do I skip items in a legend?

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henry wang
henry wang el 25 de En. de 2011
Respondida: Image Analyst el 25 de Sept. de 2024
How do I skip items in legend? Say I have 6 plots with 3 actual values and 3 interpolated curves. I only want to label the actual value curves so
legend('first','','second','','third')
doesn't really work because the interpolated curve still shows.
  14 comentarios
Greg Vieira
Greg Vieira el 4 de Sept. de 2021
How can you do this for multiple plots? For example, I have 1001 data sets plotted and only want the legend to show 1 of the first 1000 plots and the last plot. It is not reasonable for me to place 999 ' ' placeholders.
Kaveh Vejdani
Kaveh Vejdani el 10 de Jun. de 2023
First plot data1, then data1001, the set L.AutoUpdate = 'off'; % L=Legend

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Respuesta aceptada

Kenneth Eaton
Kenneth Eaton el 29 de Ag. de 2023
Editada: MathWorks Support Team el 10 de En. de 2022
Starting in R2021a, you can leave an item out of a legend by setting the corresponding label to an empty character vector. For example, plot three lines. Then call the legend function and specify the second legend label as an empty character vector. The corresponding line is omitted from the legend.
plot(rand(3)); legend('Line 1','','Line 3')
Note that this strategy works when you specify just the labels, and not when you specify a set of objects to include in the legend.
For previous releases, you can specify the objects that you want to include as the first input argument to the “legend” function.  
For example, plot three lines and return the “Line” objects as array “p”. Include only the first and third lines in the legend by specifying “p(1)” and “p(3)” as the first input argument to “legend”. 
 p = plot(rand(3)); 
 legend([p(1) p(3)],'plot 1','plot 3') 
Alternatively, you can set the “IconDisplayStyle” to “off” for the object that you do not want to include in the legend. For example, exclude the second “Line” object, “p(2)”. 
 p = plot(rand(3)); 
 set(get(get(p(2),'Annotation'),'LegendInformation'),'IconDisplayStyle','off'); 
 legend('plot 1','plot 3') 
  10 comentarios
DGM
DGM el 18 de Oct. de 2022
Editada: DGM el 18 de Oct. de 2022
I was responding to @Dan Houck who was asking specifically for a means to avoid the implicit item removal that happens in R2021a. Leaving the unlabeled marker was the goal.
As to whether what Dan asked for is visually objectionable, you're free to tell him.
Kaveh Vejdani
Kaveh Vejdani el 10 de Jun. de 2023
L = legend;
L.AutoUpdate = 'off';

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Más respuestas (13)

Matt Lobo
Matt Lobo el 1 de Nov. de 2021
Editada: Matt Lobo el 30 de Nov. de 2021
Essentially set the 'HandleVisibility' attribute to 'off' when plotting something, as such:
plot(x,y,'HandleVisibility','off')
This has some implications concerning interacting with that handle in other ways, but if you don't plan on using the handle, this is a great dynamic way to not include certain plots in your legend. It works especially well when you're plotting iteratively, and don't want to store handles and then hard-code the legend to fit your exact plot.
  5 comentarios
Andres Ricardo Herrera Orozco
Andres Ricardo Herrera Orozco el 16 de En. de 2024
Really helpful. Thanks!
Hannah Tang
Hannah Tang el 25 de Sept. de 2024
Fantastic advice. Thank you.

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Walter Roberson
Walter Roberson el 25 de En. de 2011
Editada: Rik el 5 de Abr. de 2022
You can set the IconDisplayStyle to off for the items you do not wish a legend for. See this documentation.
Edit by @Rik (2022/04/05):
The link above was valid for the documentation from R2012a. The equivalent page in R2022a suggests a different strategy (i.e. only providing the handles to legend for the objects you wish to include). In the current release IconDisplayStyle is documentated under the properties of the graphics primitives (e.g. line objects or patch objects).
Documentation pages from specific releases will remain online for 5 years.
  6 comentarios
Fernando Zigunov
Fernando Zigunov el 29 de Nov. de 2021
broken link!
Tanya Meyer
Tanya Meyer el 5 de Abr. de 2022
Yes - broken link :(

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Junette Hsin
Junette Hsin el 21 de Mzo. de 2019
Editada: Junette Hsin el 21 de Mzo. de 2019
I ran into this problem and I have not seen this method suggested yet, but I solved it by changing the order of my plotted lines which affects what the legend displays (I am using MATLAB R2017b).
Let's say you plot 2 lines first, and then create a legend. Then you plot a 3rd line. That 3rd line will be added to your legend as 'data 1'.
Instead plot 3 lines, and then in your legend, label just the first 2 lines. The 3rd line will be omitted from the legend.
Hope this helps.
  5 comentarios
Brent F
Brent F el 22 de Jun. de 2021
Editada: Brent F el 10 de Ag. de 2021
@Jim Tonti Yes! Upvote his solution: legend({'A','B'},'AutoUpdate','off')
Gabriela Belicova
Gabriela Belicova el 13 de Mayo de 2022
Both very helpful, thank you so much !!!

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Yasin Zamani
Yasin Zamani el 25 de Sept. de 2019
Editada: Yasin Zamani el 25 de Sept. de 2019
For example, suppose you want to skip the name of the first plot in the legend:
x = linspace(0, 2 * pi);
% sin(x)
h = plot(x, sin(x));
% the following line skip the name of the previous plot from the legend
h.Annotation.LegendInformation.IconDisplayStyle = 'off';
% cos(x)
plot(x, cos(x));
% legend
legend('cos');
  4 comentarios
Carl Witthoft
Carl Witthoft el 8 de Sept. de 2021
doesn't seem to work for a "fill" object
Soham Sinha
Soham Sinha el 11 de Mayo de 2022
Thanks

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Boris Blagojevic
Boris Blagojevic el 23 de Jun. de 2021
An alternative approach: Prevent the legend from updating
First, plot the lines that you want to have labeled. Then, specify the legend and set
legend(....,'AutoUpdate','off')
then, plot the remaining lines
  4 comentarios
Rik
Rik el 13 de Jun. de 2022
Comment posted as flag by Fatima u'wais:
intersted
Dr.Jaber Aljuaidiyah
Dr.Jaber Aljuaidiyah el 20 de Ag. de 2024
This works nicely. Thanks pal

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the cyclist
the cyclist el 25 de En. de 2011
Each curve has a handle, which can be obtained from the properties. Use the form of legend that takes two arguments (handle and legend), and only use the handles of those curves that you want to show.

Dilshad Raihan
Dilshad Raihan el 26 de Oct. de 2015
Editada: Dilshad Raihan el 26 de Oct. de 2015
You can do this by first plotting the curves in an order so that the lines you don't want to be displayed in the legend comes in the end. That is, suppose you have N lines to be plotted but you dont want to display m of these in the legend. Then first plot the required N-m lines and then the remaining m. After that, turn the legend on, click on the legend and the "legend property editor" will be displayed. Go to the "more properties" option. You can see an entry titled "String" specified as a "1xN cell array". Click on the cell array icon and set the size as "1xN-m". Now, only the first N-m curves will be displayed in Legend.
  1 comentario
Harish Pulluri
Harish Pulluri el 26 de Sept. de 2016
Thnak you sir, for giving the solution

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Diaa
Diaa el 17 de Nov. de 2020
Editada: Diaa el 17 de Nov. de 2020
You can simply delete the last undesired entry by the following:
% assume you plotted some curves before this line and all of them are desired to be shown in the legend
hleg = legend('show');
plot(x,y) % you don't need this plot in the legend
hleg.String(end) = []; % delete the last legend entry of the very last plot
% continue plotting while copy and paste the previous line immediately after any plot you don't need in the legend
  1 comentario
Amir Semnani
Amir Semnani el 9 de Jun. de 2021
Thanks. That worked for me (MATLAB 2017b) and it's very simple. Let's assume we have 8 datasets and we want to plot all of them, but only want to see the legend for dataset with even number.
x=ones(100,1)*(1:8); plot(x);ylim([0 9]); hleg = legend ('show'); hleg.String(1:2:end)=[];

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Akshay Ravindran
Akshay Ravindran el 26 de Nov. de 2015
Why is it that this error keeps coming up?
<<
>>
  3 comentarios
Ajith Tom George
Ajith Tom George el 17 de Nov. de 2016
If z,x,c etc are the handles, then remove the commas:
i.e. [z w c ...] and you are good to go!
Walter Roberson
Walter Roberson el 17 de Nov. de 2016
No, in each case where z w c etc are expressions that have no spaces in them, [z w c ...] is the same as [z, w, c, ...]
Spaces in expressions sometimes trigger parsing as if there were multiple expressions. For example:
[1 -2*x]
is considered two expressions, 1 and -2*x

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Luke Marsden
Luke Marsden el 2 de Feb. de 2017
I am trying to do a similar thing using this line of code:
leg = legend([p4 RETU_Average activity1 Vulcanian1], 'Tilt', 'RETU Mean Amplitude', 'Activity', '"Vulcanian" Explosions', 'Location', 'northeast');
I am getting this error:
Error using matlab.graphics.chart.primitive.Line/horzcat
Cannot convert double value 23 to a handle
Error in p1_zoom_plot (line 93)
leg = legend([p4 RETU_Average, activity1 Vulcanian1], 'Tilt', 'RETU Mean Amplitude', 'Activity', '"Vulcanian" Explosions', 'Location', 'northeast');
  4 comentarios
Brent F
Brent F el 10 de Ag. de 2021
Have you gotten this method of generating a legend using plot handles to work within a subplot?
Rik
Rik el 11 de Ag. de 2021
@Brent F A subplot is simply a new axes object, so any method should work. You should be careful when using gca or when not supplying a handle at all, as the last axes with user interaction will be the target of your calls.

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Juan Carlos de Luna
Juan Carlos de Luna el 6 de Abr. de 2020
Select line in Plot Browser and type
set(get(get(gco,'Annotation'),'LegendInformation'),'IconDisplayStyle','off')
  2 comentarios
Bart Boonstra
Bart Boonstra el 12 de Abr. de 2021
Thanks that worked for me!
Marya Sadki
Marya Sadki el 29 de Nov. de 2021
Me too thanks

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K Anderson
K Anderson el 30 de Ag. de 2024
If you plot multiple lines with the same plot command like this
h(1,:) = plot(rand(4,11),'r')
h =
1x11 Line array: Line Line Line Line Line Line Line Line Line Line Line
hold on
h(2,:) = plot(rand(4,11),'b')
h =
2x11 Line array: Line Line Line Line Line Line Line Line Line Line Line Line Line Line Line Line Line Line Line Line Line Line
and use
legend
on this, you get a 2x11 long legend
but you only want to highlight the first red and first blue line use this;
legend([h(1,1) h(2,1)],'red','blue')
This is mentioned in the documentation as;
legend(subset,___) only includes items in the legend for the data series listed in subset. Specify subset as a vector of graphics objects. You can specify subset before specifying the labels or with no other input arguments.

Image Analyst
Image Analyst el 25 de Sept. de 2024
Every time you plot, get the handle to the points or curves. Then pass only those that you want into legend. Here is a full demo:
lineSize = 2;
markerSize = 30;
% Define 3 data sets
x1 = [-1.9, 0.004, 1.94];
x2 = [-1.94, -0.23, 1.95];
x3 = [-1.92, .2, 1.93];
y1 = [13.885, 10.168, 14.235];
y2 = [9.3805, 5.2697, 9.3367];
y3 = [4.5262, 0.80904, 4.0889];
% Interpolate the 3 curves.
xFit = linspace(-2, 2, 500);
coefficients1 = polyfit(x1, y1, 2);
yFit1 = polyval(coefficients1, xFit);
coefficients2 = polyfit(x2, y2, 2);
yFit2 = polyval(coefficients2, xFit);
coefficients3 = polyfit(x3, y3, 2);
yFit3 = polyval(coefficients3, xFit);
% Plot the 3 data sets and their interpolated curves
handle1 = plot(x1, y1, 'r.', 'MarkerSize', markerSize);
hold on;
handle2 = plot(xFit, yFit1, 'r-', 'LineWidth', lineSize);
handle3 = plot(x2, y2, 'b.', 'MarkerSize', markerSize);
handle4 = plot(xFit, yFit2, 'b-', 'LineWidth', lineSize);
handle5 = plot(x3, y3, 'g.', 'MarkerSize', markerSize);
handle6 = plot(xFit, yFit3, 'g-', 'LineWidth', lineSize);
grid on;
% Have the legend only for the data, not the interpolated fit
% by passing in only the plot handles of the data.
legend([handle1, handle3, handle5], 'Data1', 'Data2', 'Data3', 'Location', 'north');

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