How do you produce an empty plot if value is higher or lower than given user input value?

The .mat file has data for years, names, yearReconstruct

clear;
close all;

% Part 1
userInput=input("Please choose between the following numbers: 1 or 2");

% Part 2
circuit("power.mat",userInput);

% Part 3 to 5 - function implementation for bridges & branches
function circuit(power,userInput)
power=load(power); 
figure();

    if userInput==1
        y=power.years;
        custom = 'v r';
        z='Year';
    else
        if userInput == 2
              y = power.yearReconstruct;
            y(power.yearReconstruct==0)= NaN;
            custom = '* b'; 
            z='Reconstruction Year';
        else
            y=[];
            custom=[];
            disp("Invalid input value, input must be either 1 or 2");
        end
        end
    end   
hold on
x=power.names;
plot(y,custom,'Markersize',10,'lineWidth',2);
xlabel('voltage');
ylabel(z);
grid on
set(gca,'xticklabel',x.')
xtickangle(-45);

end
   

I keep getting an error and it still gives me part of a plot.

Answer 1

[Walter Roberson]

            y=nan;
            custom=nan;

If you want to produce an empty plot for that case. Your current code will not produce any plot for that case.