How to change font size of right axis of Pareto plot in Matlab - matlab

Question

I am trying to bold the right side y axis for a Pareto plot in Matlab, but I can not get it to work. Does anyone have any suggestions? When I try to change the second dimension of ax, I get an error:
"Index exceeds matrix dimensions.
Error in pcaCluster (line 66)
set(ax(2),'Linewidth',2.0);"
figure()
ax=gca();
h1=pareto(ax,explained,X);
xlabel('Principal Component','fontweight','b','fontsize',20)
ylabel('Variance Explained (%)','fontweight','b','fontsize',20)
set(ax(1),'Linewidth',2.0);
set(ax(1),'fontsize',18,'fontweight','b');
%set(ax(2),'Linewidth',2.0);
%set(ax(2),'fontsize',18,'fontweight','b');
set(h1,'LineWidth',2)

Answer 1

Actually you need to add an output argument during the call to pareto and you will then get 2 handles (the line and the bar series) as well as 2 axes. You want to get the YTickLabel property of the 2nd axes obtained. So I suspect that in your call to pareto above you do not need to supply the ax argument.
Example:
[handlesPareto, axesPareto] = pareto(explained,X);
Now if you use this command:
RightYLabels = get(axesPareto(2),'YTickLabel')
you get the following (or something similar):
RightYLabels =
'0%'
'14%'
'29%'
'43%'
'58%'
'72%'
'87%'
'100%'
What you can do is actually to erase them altogether and replace them with text annotations, which you can customize as you like. See here for a nice demonstration.
Applied to your problem (with dummy values from the function docs), here is what you can do:
clear
clc
close all
y = [90,75,30,60,5,40,40,5];
figure
[hPareto, axesPareto] = pareto(y);
%// Get the poisition of YTicks and the YTickLabels of the right y-axis.
yticks = get(axesPareto(2),'YTick')
RightYLabels = cellstr(get(axesPareto(2),'YTickLabel'))
%// You need the xlim, i.e. the x limits of the axes. YTicklabels are displayed at the end of the axis.
xl = xlim;
%// Remove current YTickLabels to replace them.
set(axesPareto(2),'YTickLabel',[])
%// Add new labels, in bold font.
for k = 1:numel(RightYLabels)
BoldLabels(k) = text(xl(2)+.1,yticks(k),RightYLabels(k),'FontWeight','bold','FontSize',18);
end
xlabel('Principal Component','fontweight','b','fontsize',20)
ylabel('Variance Explained (%)','fontweight','b','fontsize',20)
which gives this:
You can of course customize everything you want like this.

Answer 2

That is because ax is a handle to the (first/left) axes object. It is a single value and with ax(1) you got lucky, its ax again, but ax(2) is simply not valid.
I suggest to read the docs about how to get the second axis. Another good idea always is to open the plot in the plot browser, click whatever object you want so it is selected and then get its handle by typing gco (get current object) in the command window. You can then use it with set(gco, ...).