How to make horizontal and vertical axis in matlab plot?

I would like to make a plot which includes the x-axis and the y-axis. So x=0 and y=0. What is the most easy way to do this? Now I have this:

syms x y;
x=-4:4;
y=90-15*x; 
plot(x,y); 
grid on;
xlabel('x');
ylabel('y');

Answer 1

[Image Analyst]

Try adding this:

grid on;
line([0,0], ylim, 'Color', 'k', 'LineWidth', 2); % Draw line for Y axis.
line(xlim, [0,0], 'Color', 'k', 'LineWidth', 2); % Draw line for X axis.

It doesn't move the tick marks and tick labels for you but it will draw thick black lines where the axes are so that they don't look just like any other grid line.

[Lisanne Hogeveen]

Thanks!

[Image Analyst]

Thanks for accepting!

I wish there were some option to have the tick marks and labels show up along the actual axes instead of the edge of the whole plot/graph, but I don't know of an easy way to do that, short of using text() to draw all the labels yourself. If there is, someone please tell us.

[UPDATE] - there is now. See my other answer.

[Steven Lord]

Should we switch to make your other answer the Accepted answer instead of this one?

[Image Analyst]

@Steven Lord Probably, since most people now will be using modern versions where they can do what I did there in the newer Answer. I think they were unavailable way back in 2016 when I originally answered the question. I unaccepted the old answer but I can't accept my own, new answer so it would be great if you do it. Thanks. 🙂

Answer 2

[Image Analyst]

Try this:

% Method #1:
figure;
x = -4:11;
y = 90 - 15 * x; 
plot(x, y, 'b-', 'LineWidth', 2); 
grid on;
xlabel('x');
ylabel('y');
% Place black lines along axes:
xline(0, 'Color', 'k', 'LineWidth', 2); % Draw line for Y axis.
yline(0, 'Color', 'k', 'LineWidth', 2); % Draw line for X axis.

% Method #2
figure;
plot(x, y, 'b-', 'LineWidth', 2); 
grid on;
xlabel('x');
ylabel('y');
ax = gca;
ax.XAxisLocation = 'origin';
ax.YAxisLocation = 'origin';