How to draw lines in matlab figure

Hi everyone, I plot simple figure in matlab by using plot(x,y).now I need to draw verticale dashed lines like grid lines at some specific points on x-axis.,what should I do? thanks

Answer 1

[Star Strider]

Try this:

x = 0:20;
y = sin(x*pi/9);

figure(1)
plot(x, y);
hold on
plot([1 1]*4.5, ylim, '--k')                % First Vertical Line at ‘x=4.5’
plot([1 1]*13.5, ylim, '--k')               % First Vertical Line at ‘x=13.5’
hold off
grid

Also, I like your Emperor penguins!

[Omkar Paranjape]

How to draw horizontal lines?

[Star Strider]

plot(xlim, [1 1]*4.5, '--k')                % First Horizontal Line at ‘y=4.5’
plot(xlim, [1 1]*13.5, '--k')               % First Horizontal Line at ‘y=13.5’

Answer 2

[Steven Lord]

You could either turn the grid on or use the xline and/or yline functions.

plot(1:10);
grid on
xline(4.5, 'r:')
yline(2*pi, 'c--', 'LineWidth', 2)

With xline and yline, if you pan or zoom the axes the lines still extend to the limits of the axes.