skip items in a legend

i see this post

https://it.mathworks.com/matlabcentral/answers/406-how-do-i-skip-items-in-a-legend

but i don't understan how resolve it

i don't want visualize 'str2' in legend

str1='A';

str2='';

str3='C';

legend(str1,str2,str3,'Location','northwest')

Warning: Ignoring extra legend entries.

> In legend>process_inputs (line 592)

In legend>make_legend (line 319)

In legend (line 263)

In Predator_grafici_Struct (line 67)

Answer 1

[Star Strider]

Perhaps this —

x = 0:10;
y1 = randn(size(x));
y2 = randn(size(x));
y3 = randn(size(x));

figure
hp1 = plot(x, y1, 'DisplayName','A');
hold on
hp2 = plot(x, y2, 'DisplayName','B');
hp3 = plot(x, y3, 'DisplayName','C');
hold off
grid
legend([hp1 hp3], 'Location','best')

.

[Luca Re]

hold(Ax_Eq, 'on')

if Set.ShowOne

hp1=plot(Ax_Eq,XDates,TEE1,'A','Color','black');

end

hp2=plot(Ax_Eq,XDates,TEE2,'B','Color',[0 0.4470 0.7410]);

if Set.ShowUnfiltered

hp3=plot(Ax_Eq,XDates,TEE3,'C','Color','red');

end

ytickformat(Ax_Eq,'usd');

axis(Ax_Eq, 'tight');

disableDefaultInteractivity(Ax_Eq)

grid(Ax_Eq,"on");

%legend(Ax_Eq,'Unfiltered','Filtred','Location','northwest');

legend([hp1 hp2 hp3],'Location','northwest');

sett=extractBefore(Set.tslist,'.');

title(Ax_Eq,sett);

hold(Ax_Eq, 'off')

Unrecognized function or variable 'hp1'.

Error in Predator_grafici_AppDesigner_Struct (line 58)

legend([hp1 hp2 hp3],'Location','northwest');

[Image Analyst]

Basically, to have the legend() function display only some of the curves you have already plotted, you have to keep track of the handles to the curves you plotted and then you pass in ONLY the handles to the curves you want legend() to show. But you did this

legend([hp1 hp2 hp3],'Location','northwest');

which would show all 3 curves (if all 3 of those existed). However you never assigned hp1 so you can't tell legend to use it because it does not exist - you never created hp1.

[Star Strider]

@Luca Re — This error:

Unrecognized function or variable 'hp1'.

appears because the first plot is only executed if ‘Set.ShowOne’ is true, so if that condition is not met, ‘hp1’ will not be created.

One approach to fixing that would be to set ‘hp1’ and ‘hp3’ (since it also will only be executed if ‘Set.ShowUnfiltered’ is true) to empty values first —

x = 0:10;
y1 = randn(size(x));
y2 = randn(size(x));
y3 = randn(size(x));

hp1 = [];
hp3 = [];

Set.ShowOne = 0;
Set.ShowUnfiltered = 1;

figure
if Set.ShowOne
    hp1 = plot(x, y1, 'DisplayName','A');
end
hold on

hp2 = plot(x, y2, 'DisplayName','B');

if Set.ShowUnfiltered
    hp3 = plot(x, y3, 'DisplayName','C');
end
hold off
grid
legend([hp1 hp2 hp3], 'Location','best')

This does not plot ‘hp1’ because the condition ‘Set.ShowOne’ is not met, and because ‘hp1’ has already been defined as ‘empty’, the error you got is not thrown in this code example. The third plot that creates ‘hp3’ plots and shows in the legend because ‘Set.ShowUnfiltered’ is true, and ‘hp3’ over-writes the previously set ‘empty’ value, so it appears in the legend call.

.

[Luca Re]

correct! thank

[Star Strider]

As always, my pleasure!