Assign values to multiple subplots for secondary y axis

I have a graph that is plotting 100 different subplots. Each subplot has an x axis (degrees) and y axis (intensity), and also refers to a different load during tensile testing. For example, file one is 20N, file two is 30N, etc etc. I have my subplot working perfectly but I am trying to read the load values from a xls file and want to assign the first value in that spreadsheet to the first subplot, and so on, and to use this as a second y-axis. This is my code so far but I can't figure out how to assign the load to each file. (I have excluded my filepaths from the directories for this question just in case someone points that out.) I would really appreciate it if someone could help!

close all
clear all
clc %Closes opened figures

%D is directory - where the files are saved.
D = '.......';
S = dir(fullfile(D,'*txt')); % only looking at .txt files
N = numel(S); %N = number of .txt files
C = cell(1,N);

F1 = fullfile('........'); %reading files
C1 = xlsread(F1,'A2:A108');
M = numel(C1);
for k = 1:N %reads every second file. If you want to read all files, use "for k = 1:N" instead.
    F = fullfile(D,S(k).name); %reading files
    T = importdata(F,' ',20); %converting files into a table
    C{k} = T.data;
    F1 = fullfile('......'); %reading files
    
    
    x = (C{k}(:,1:1)); %2 theta 
    y = (C{k}(:,2:2)); %Intensity%    
  
    plot(x,y,'b');
    set(gca,'YTickLabel',[]); %removes y axis values
    title('Diffraction Waterfall Plot')
    xlabel('2 theta');
    ylabel('Intensity');
  

plot(x,y)
hold on
end 

[Seth Furman]

Can you attach an example of your data?

Am I correct in understanding the following?

• Each file has one set of x and y-values.
• You'd like to plot each set of x and y-values on a separate subplot.

[Frances Synnott]

Hi Seth, this is an example of the data I would like to plot. At the moment, I have 100 files each with their own x and y data that I would like to plot like the figure below. At the moment, I have been able to plot it like this by off setting the y axis for each subsequent plot to get this waterfall effect. However, I have another csv file that says file one = 20N, file two = 40N etc etc like the second y-axis in the image. So what I am looking to do is to write code that says file one = column one,cell one in the spreadsheet, file two = column one, cell two etc etc so I can plot a waterfall plot with two axes. I hope this makes sense! Thanks.

Answer 1

[Raj Bhakta]

Frances,

Are you attempting to keep each dataset (20N, 40N, ...) on it's own separate subplot? If so, you can try something like this:

figure;
subplot(3,1,1)
hAx = plot(1:10, rand(10,1));
yyaxis left; ylabel('Left Side 1'); set(gca,'YTick',[]);
yyaxis right; ylabel('Right Side 1')
subplot(3,1,2)
plot(1:10, rand(10,1))
yyaxis left; ylabel('Left Side 2'); set(gca,'YTick',[]);
yyaxis right; ylabel('Right Side 2')
subplot(3,1,3)
plot(1:10, rand(10,1))
yyaxis left; ylabel('Left Side 3'); set(gca,'YTick',[]);
yyaxis right; ylabel('Right Side 3')

I hid the left y axis because you're using it more as a title (20N,40N,...) instead of as a scale. Is this what you're looking for?

[Frances Synnott]

Hi Raj, I'm looking to plot each file on the sample plot, just like a waterfall plot. As the loads I am looking at don't increase with equal increments, such as 20N, 40N...85N for example, I need to find a way that assigns the first plot to the first cell of another csv and so on. Thank you for your help though.

[Raj Bhakta]

Frances,

I think I understand. Is the load condition recorded somewhere in your txt file that you're reading in or in the name of the file? You can convert that string to a number and use this as your offset to move up the waterfall by your load increment.

loadOffset = 0; % The initial offset on the 2nd y axis is 0

for k = 1:N %reads every second file. If you want to read all files, use "for k = 1:N" instead.
    
    F = fullfile(D,S(k).name); %reading files
    T = importdata(F,' ',20); %converting files into a table
    C{k} = T.data;
    
    newLoading = str2num(C{k}(row,col)); % Get the loading offset
    loadOffset = loadOffset + newLoading;
    
    x = (C{k}(:,1:1)); %2 theta 
    y = (C{k}(:,2:2)); %Intensity%    
    
    y = y + loadOffset; % Add the load offset to all y values
  
    plot(x,y,'b');
    set(gca,'YTickLabel',[]); %removes y axis values
    title('Diffraction Waterfall Plot')
    xlabel('2 theta');
    ylabel('Intensity');
  
plot(x,y)
hold on
end 

Would this work?