Set XTick of yyaxis to have integer ticks only

I have a plot with double y axes using yyaxis. I want to set XTick to have only integer values, e.g., 1, 2, 3, 4, 5, 6, instead of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6.

With normal plot, I can just use:

ax = gca;
ax.XTick = unique(round(ax.XTick));

to achieve this goal.

But this seems not the case for yyaxis plot.

Please help!

---

Update: here is a MWE to illustrate my problem:

figure('Position', get(0, 'Screensize'));

max_iter = 100;
A_history = nan(1,max_iter); B_history = nan(1,max_iter);
for iter = 1 : max_iter
    yyaxis left;
    A_history(iter) = randn(1);
    plot(A_history(1:iter), '-ob', 'LineWidth', 0.9, 'MarkerSize', 4.5, 'MarkerFaceColor', 'b');
    ylabel('first yaxis');
    
    yyaxis right;
    B_history(iter) = randn(1);
    plot(B_history(1:iter), '-or', 'LineWidth', 0.6, 'MarkerSize', 3, 'MarkerFaceColor', 'r');
    ylabel('second yaxis');
    
    %     ax = gca;
    %     ax.XTick = unique(round(ax.XTick));
    pause(1);
end

The above code will create xticks of 0, 0.1, 0.2, 0.3, 0.4, ..., 1 for the 1st iteration; xticks of 1, 1.1, 1.2, 1.3, 1.4, ..., 2 for the second iteration, for example.

What I want is to get rid of all the non-integer values (e.g., 0.1, ... ,0.9, 1.1, ... ,1.9) in the xticks, just leave integer values (e.g., 0,1 for the 1st iteration; 1,2 for the second iteration).

I have tried to add the commented 2 lines of code. But they don't give me the expected result, unfortunately. What's worse is that the xticks would become [0,1] all the time...

Hope this makes the problem description clearer.

[Adam Danz]

It should work.

yyaxis right
plot(rand(1,20)*4, rand(1,20), '*')

yyaxis left
plot(rand(1,20)*6, rand(1,20), '*')

ax = gca;
ax.XTick = unique(round(ax.XTick));

[hmhuang]

@Adam Danz My xticks are actually changing in each iteration, not fixed as your example shown. Can you please have a look at my updated post? Thanks!

[Adam Danz]

Then you probably just need to set xlim.

Answer 1

[dpb]

yyaxis right
plot(rand(1,20)*4, rand(1,20), '*')
yyaxis left
plot(rand(1,20)*6, rand(1,20), '*')
hAx=gca;                                % retrieve handle to current axes
hAx.YAxis(2).TickLabelFormat='%d';      % set RH y axis format string to integer

NB: the subscript on the YAxis handle array -- the specialized axes object created by yyaxis is a super axes container that has both LH and RH axes objects inside. The first array element is LH, the second the RH axis.

[hmhuang]

@dpb Sorry...This is not what I want....Please see the updated post.

[dpb]

  ...
  xlm=xlim;
  xticks(xlm(1):xlm(2))
end

[hmhuang]

@dpb Thanks! But this will cause overlapped xticks in the end when we have a large max_iter, say 1000.

[Adam Danz]

In the example from your question,

% To show the full plot from the start of the animation
ax = gca(); 
ax.XLim = [1,max_iter];
ax.XTick = unique(round(linspace(1,max_iter, 10)));  % for up to 10 ticks

or

% To animate the x axis limits
ax = gca(); 
ax.XLim = [0,iter];
ax.XTick = unique(round(linspace(1,max_iter, 10)));  % for up to 10 ticks

[dpb]

  ...
  xtk=xticks;
  xticks(xtk(xtk==fix(xtk)))
end