How can I draw horizontal X(0,0) single grid line?

Just wondering, I need to show the central X(0,0) line visible (and not other grids) in my plot where there have positive and negative values with Y axis? I tried this to draw the line,

line([0 84436], [0 0]);

But, it comes in the legend lists (which obviously should not be) and it does not give black or grid colour.

Any suggestion is much appreciating.

Answer 1

[John D'Errico]

This will draw a reference line, with a slope and intercept of 0.

refline(0,0)

However, I do see that it does show up if I use legend, with no arguments. So this shows the refline in the legend:

plot(randn(1,10),randn(1,10),'o')
refline(0,0)
legend

Instead, I can call legend with my own descriptions. So if there are 3 curves, just call legend with 3 names.

plot(randn(10,3),randn(10,3),'o')
refline(0,0)
n = 3;
legtit = cell(1,n);
for i = 1:n
  legtit{i} = ['Data ',num2str(i)];
end
legend(legtit(:))

As you can see, no refline in the legend.

[Khondokar Fida Hasan]

In my case if I declare refline(0,0) before plot, it just work fine. No legend for it. But after the plot, it comes as a legend.