I am trying to plot but I am getting an empty figure

I am trying to plot but I am getting an empty figure. I am not sure what is wrong with my code.

for Tf=32:1:212
p=133.3*exp(20.386-(51.32/((9/5)*Tf+32)))
zf(1) = figure(1);
    za(1) = axes;
    plot(Tf,p,'r')
    xlabel('Temperature (F)')
    ylabel('Pressure (Pa)')
    xlim([0 215]);
    ylim([0 10e10]);
end

Answer 1

[Adam Danz]

There are two problems.

1. When you're plotting only 1 coordinate at a time, specify a marker type.
2. You need to apply "hold on" to your axes \

Also, there are other inefficiencies in your loop. See the reconstructed loop and comments below.

% Move this stuff out of the loop!
zf(1) = figure(1);
za(1) = axes;
hold(za(1), 'on')  % <--- don't forget this!

for Tf=32:1:212
    p=133.3*exp(20.386-(51.32/((9/5)*Tf+32))); % <-- suppress output with ";"
    plot(Tf,p,'ro') %<--- specify a marker!
end

% Move this stuff out of the loop!
xlabel('Temperature (F)')
ylabel('Pressure (Pa)')
xlim([0 215]);
ylim([0 10e10]);

The loop can be replaced with vectorized format. This version below is much more efficient and produces the same plot (except for line style).

Tf = 32:1:212;
p = 133.3*exp(20.386-(51.32./((9/5).*Tf+32)));
plot(Tf,p,'b','lineWidth',2)

The plot below shows the loop method (red markers) and the vectorized method (blue line).