Whats wrong with the following commands?

% The plotted x-axis goes from 0 to 1, instead of 20. Why?

ax = gca;

ax.xlim = [0 20];

drawnow

[@Johannes]

I have a small example for you

   time=[0:2:24];
   data=[5;6;12;18;15;16;18;15;10;9;8;7;7];

   figure(1);  

   plot(time,data,'r','LineWidth',2);
   ax=gca;
   ax.XLim = [0 20];

   grid on;
   title('test','fontsize',12,'fontweight','bold');
   xlabel('x-axis','fontsize',12,'fontweight','bold');
   ylabel('y-axis','fontsize',12,'fontweight','bold');

Regards, John

[the cyclist]

This code worked as expected for me. See attached.

[Mr M.]

yes, but you can see, that I want to set axes before drawing the plot or plotting anything! This is not possible? The problem is that axes are created with the plot command and not existed before? How to set axes before and plot shapes after?

Answer 1

[Steven Lord]

By default, calling PLOT resets most of the axes properties. See the description of "hold off" in the documentation for HOLD as well as the description of the axes property NextPlot for more information. To do what you want, use HOLD or the NextPlot axes property.

Answer 2

[the cyclist]

This code worked for me:

figure
plot(rand(7,5))
ax = gca;
ax.XLim = [0 20];
drawnow

(I changed the capitalization of ax.XLim.)

[Mr M.]

yes, but you can see, that I want to set axes before drawing the plot or plotting anything! This is not possible? The problem is that axes are created with the plot command and not existed before? How to set axes before and plot shapes after?

[the cyclist]

disp('Create the figure window with default axes, and "hold" so that later axes add on, rather than replace.')
figure
hold on
pause(2)

disp('Resize the axes')
ax = gca;
ax.XLim = [0 20];
pause(2)

disp('Add a plot')
plot(rand(7))
pause(2)

disp('Bye bye')

[Mr M.]

This is NOT working for me!

figure;
hold on;
ax = gca;
ax.XLim = [0 20];
plot([],[]);
drawnow;

[the cyclist]

Strange. Works for me. The output of those commands is attached below. (R2015a on Mac OS X 10.10.5.)

[Mr M.]

my otput is the same but x-axis goes to 1 instead of 20! I cannot understand why?!

[@Johannes]

I hope this fixes your Problem. With hold(ax,'on') it is not possible for the plot command to update the axis.

 figure
ax = gca;
ax.XLim = [0 20];
hold(ax,'on') 
plot([],[])

Regards, John