How do I plot a horizontal line on my existing graph?

I have a MATLAB plot of a graph consisting of values input into a matrix R of size R x 1.

On the same graph I want to plot a horizontal line of fixed value k.

How do I do this? I tried using the yline() function to no avail.

My code to plot the graph is:

plot(R)

Trying to add the horizontal line I tried:

plot(R,yline(k))

But it does not work. Any advice?

Answer 1

[Dyuman Joshi]

You need to use it as a separate command

%Random data for example
R = rand(10,1);
k = rand;

%plot the matrix
plot(R)
yline(k)