problem with hold on into a subplot inside a for loop

hi,I've a problem with the command 'hold on' into a subplot inside a for loop, it don't give me the overlap of the second curve of each graph. In the script I take many data from excel:

    function cnr3
    sheetnames = { '15x5_003','15x5_004','15x5_005' };
    n = length(sheetnames);
    %plotta p-theta e segnale inj
    for idx = 1:n
        A = xlsread('prove.xlsx',sheetnames{idx},'A3:A3603');
        B = xlsread('prove.xlsx',sheetnames{idx},'B3:B3603');
        C = xlsread('prove.xlsx',sheetnames{idx},'C3:C3603');
        hold on   
        subplot(1,3,1)
        [ax,h1,h2] = plotyy(A,B,A,C)
        set(ax(1), 'XLim',[-60 60]);
        set(ax(2), 'XLim',[-60 60]);
        set(ax(1), 'YLim',[0 inf]);
        set(ax(2), 'YLim',[0 120]);
        set(ax(1), 'YTick',[0:20:240]);
        set(ax(2), 'YTick',[0:20:120]);
        xlabel('CA [deg]')
        ylabel(ax(1),'p cyl [bar]')
        ylabel(ax(2),'EC [A]')
        title('1500x5')
        hold off
    end

    for idx = 1:n

        %plotta HR [%] e HRR[%/deg]
        [A]=xlsread('prove.xlsx',sheetnames{idx},'A3:A3603');
        [D]=xlsread('prove.xlsx',sheetnames{idx},'D3:D3603');
        [E]=xlsread('prove.xlsx',sheetnames{idx},'E3:E3603');
        hold on
        subplot(1,3,2)
        [ax,h1,h2] = plotyy(A,D,A,E)
        set(ax(1), 'XLim',[-30 60]);
        set(ax(2), 'XLim',[-30 60]);
        set(ax(1), 'YLim',[-10 100]);
        set(ax(2), 'YLim',[-inf inf]);
        set(ax(1), 'YTick',[0:20:120]);
        set(ax(2), 'YTick',[-10:4:50]);
        xlabel('CA [deg]')
        ylabel(ax(1),'HR [%]')
        ylabel(ax(2),'HRR [%/deg]')
        title('1500x5')
        hold off
    end
    for idx = 1:n  
       %plotta HR [kJ/m^3]e HRR[kJ/m^3 deg] 
       [A]=xlsread('prove.xlsx',sheetnames{idx},'A3:A3603');
       [F]=xlsread('prove.xlsx',sheetnames{idx},'F3:F3603');
       [G]=xlsread('prove.xlsx',sheetnames{idx},'G3:G3603');
       hold on
       subplot(1,3,3) 
       [ax,h1,h2] = plotyy(A,F,A,G)
       set(ax(1), 'XLim',[-30 60]);
       set(ax(2), 'XLim',[-30 60]);
       set(ax(1), 'YLim',[-inf inf]);
       set(ax(2), 'YLim',[-inf inf]);
       set(ax(1), 'YTick',[0:200:6000]);
       set(ax(2), 'YTick',[0:15:600]);
       xlabel('CA [deg]')
       ylabel(ax(1),'HR [kJ/m^3]')
       ylabel(ax(2),'HRR [kJ/m^3 deg]')
       title('1500x5')
       hold off
    end

At the end,it give me this:

but it's incomplete,I would have somthing like this for all three subplots:

I will be very grateful for every your edvice

Answer 1

[dpb]

Several issues here...

First, regarding hold and its use -- in general it's undesirable to set hold on until after the first plot into the given axes object is made via plot or other high-level plotting routine.

Secondly, it ONLY affects one axes at a time; for some reason I've never fathomed, TMW did not vectorize it; you can only set one axes at a time with hold...and plotyy creates two axes so to add to each of those, both axes' nextplot property must be set. This is either going to be

hold(ax(1)'on'), hold(ax(2)'on')

or,

set(ax,'nextplot','add')

for simultaneously setting both.

But, compounding the issue, you're overwriting the axes and line handles each pass through the loop so you've lost the handles to the first set of axes the next time through by not incrementing a counter to make them an array...

The better way would be to read the data into arrays, then plot it all in "one swell foop" instead...

for idx = 1:n
  dat=xlsread('prove.xlsx',sheetnames{idx});  % get all the data from spreadsheet
  A(:,idx)=dat(:,1);                               % create some local variables of
  B(:,idx)=dat(:,2);                               % the desired columns from
  C(:,idx)=dat(:,3);                               % multiple worksheets
end
subplot(1,3,1)
[hAx(1,:),hL1(1,:),hL2(1,:)]=plotyy(A,B,A,C);
linkaxes(ax,'x')          % link the x axes to keep in synch
set(ax(1), 'XLim',[-60 60]);
set(ax(1), 'YLim',[0 inf],'YTick',[0:20:240])
set(ax(2), 'YLim',[0 120])'YTick',[0:20:120])
xlabel('CA [deg]')
ylabel(ax(1),'p cyl [bar]')
ylabel(ax(2),'EC [A]')
title('1500x5')

Now you don't actually need hold at all; you may want to set line colors manually, not sure how later releases treat, but probably still will cycle the multiple lines on the two axes. If so, then

set(hhL1(1,:),'color','b'),set(hL2(1,:),'color','g')

will do the trick.

Rearrange the other subplots similarly excepting, of course, use the correct columns out of the dat array as desired and keep the handles of the axes and lines in 2D arrays (or cell array if aren't same number of lines in each subplot).