How do I use the plot function if I have to plot along the (y = constant) or (x=constant)?

I am stuck in a very basic problem but I need help.I want to keep 'x coordinate' constant and plot for y(the values for y theoretically should vary from positive infinity to negative infinity). What would be the procedure if we want to do the same for 'y' i.e 'y coordinate'as constant and varying x from positive infinity to negative infinity.

Answer 1

[Walter Roberson]

yL = ylimit();
plot([constant_x, constant_x], YL);

and

xL = xlimit();
plot(xL, [constant_y, constant_y]);

This code draws between the current plot limits, since you cannot draw infinitely. The distinction of plot limits matters if you are planning to allow the user to pan (scroll) areas that are not currently visible: the code above does not by itself create an effectively infinite line segment that should be drawn no matter how far the user pans.

[Stephen23]

Undocumented, but this draws an "infinite" line:

fgh = figure();
axh = axes('Parent',fgh);
lnh = plot(axh,[1,1],[0,1]);
fun = @(~,evt)set(lnh,'YData',get(evt,'NewValue'));
addlistener(axh, 'YLim', 'PostSet',fun);