legend() has an issue with 'Selected' or 'selected'

The command legend() has an issue with 'Selected' as a legend name.

E.g.:

t = -13:13;
A = t*2-3*t; 
B = A(A>0);
figure
plot(t, A, 'r-'), hold on
ts = t(A>0);
plot(ts, B, 'ko'), grid on
legend('All data', 'selected')

The above code prompts the following error:

Error using legend (line 272)

Mismatched number of name-value pair arguments. Specify a property

value for each property name.

Error in Untitled8 (line 8)

legend('All data', 'selected')

---

Any comments or suggestions how to address this issue is appreciated.

Thank you.

Answer 1

[Cris LaPierre]

The problem here is that 'selected' is being interpreted as the name of a name-value pair.

Change you legend labels to a cell array of character vectors to remove the ambiguity.

t = -13:13;
A = t*2-3*t; 
B = A(A>0);
figure
plot(t, A, 'r-'), hold on
ts = t(A>0);
plot(ts, B, 'ko'), grid on
legend({'All data', 'selected'})

[Sulaymon Eshkabilov]

Good point. Thanks - Cris.

[Steven Lord]

Another way to handle this is to set the DisplayName property of the objects that you want to appear in the legend.

% Make some sample data
x = 0:360;
y1 = sind(x);
y2 = cosd(x);

% Set up the axes
axis([0 360 -1 1])
hold on

% Plot
plot(x, y1, 'ro-', 'MarkerIndices', 1:30:numel(x), 'DisplayName', 'Selected')
plot(x, y2, 'kx--', 'MarkerIndices', 15:30:numel(x), 'DisplayName', 'MarkerIndices')

% Show the legend
legend show

I set the MarkerIndices property as well so I could show a subset of the points that were plotted as markers. Even though that's a property of the plotted line I could still use it as the DisplayName.

[Sulaymon Eshkabilov]

Thanks - Steven. This is a very nice syntax.