Error using legend MATLAB R2019b

I get the following error while doing a plot in MATLAB 2019b on Windows 10:

"Error using legend (line 279) Element 1 is not a string scalar or character array. All elements of cell input must be string scalars or character arrays"

even though the arguments passed to the legend function are correct.

The error occurs only every third time or so with the exact same code... (The ylabel, xlabel and title functions work perfectly.) The code used was the following:

for i = 1:2

ylabel(obj.hAxis{i}, axisUnits)

xlabel(obj.hAxis{i}, 'Measurement Sample')

title(obj.hAxis{i}, [obj.signalId '-' sideArray{i}])

legend(obj.hAxis{i},[signalLabels], 'Location','EastOutside')

end

The following suggestion from another question: "opengl('save','software')" did not help.

Neither did storing the obj.hAxis{i} in a temporary variable and passing this temporary variable to the legend function.

Answer 1

[Peng Li]

what is your signalLabels? Is that a cell or a string matrix?

[Matthieu Assa]

it's a cell

[Peng Li]

Is that possible that you can show it's elements here? Or you can try make it string explicitely by string(signalLabels)?

[Matthieu Assa]

Thanks a lot! making it a string explicitely solved the issue for me! (now it worked 40/40 times) :)

Although it still remains a bit confusing that with a cell it worked 24/40 times and failed 16/40 times... But now that I know how to solve the issue it doesn't matter anymore.