Why is the line in my figure not showing up?

I have multiple plots in same axes so i want to have 2 separate lines connecting the plots respectively. However my line is not showing eventhough my x and 0 marker shows up. What is the problem in my linespec?

for i=1:20;
    %TR1 is my output 1 and TY is my output 2  %
plot(i,TR1(i),'-rx',i,TY(i),'-bo','LineWidth',2)
    if i == 1
       hold on
    end
end
hold off

Here is the figure i get

P/S: my matlab version is R2018a

Answer 1

[Mark Sherstan]

Create the plot after your loop (or dont use a loop at all) as so:

... end

figure(1))
x = 1:length(TR1);

plot(x,TR1,'-rx',x,TY,'-bo','LineWidth',2)

[Shay Ang]

Thank you, this syntax works on my codes!

Answer 2

[Walter Roberson]

Each call to plot produces new primitive line objects. Different primitive line objects do not join together .

You are only plotting one point at a time so nothing you plot will join with anything else .

No loop.

plot(1:20, TR1(1:20), .......)

[Shay Ang]

Thank you, this syntax works on my codes!