Loop through and plot columns in excel

I need to call from an excel sheet and assign the first two columns to X and Y variables. I use these variables in a calculation and then I need to plot them.

Then I need to loop through the next two columns in the excel sheet (columns 3+4) and assign these to X and Y and run the calculation again and then plot the results. I already have the code for the calculation so I'm just stuck on looping through the columns and the graphing. This is what I have:

filename = 'samplefile.xlsx';
File = xlsread(filename);
sheet = 1;
xlRange = 'A14:A1013';
xlRange2 = 'B14:B1013';
x = xlsread(filename,sheet,xlRange);
y = xlsread(filename,sheet,xlRange2);

- There is a variable number of columns in each file but the same number of rows.

Answer 1

[Image Analyst]

You forgot to attach your workbook. But I'll give it a guess. Try this (untested)

filename = 'samplefile.xlsx';
data = xlsread(filename);
[rows, columns] = size(data);
for col = 1 : 2 : columns
    x = data(14:1013, col);
    y = data(14:1013, col + 1);
    plot(x, y, '-', 'LineWidth', 2);
    hold on;
end
grid on;
xlabel('X', 'FontSize', 20);
ylabel('Y', 'FontSize', 20);
title('Y vs. X', 'FontSize', 20);

Answer 2

[dpb]

Fuggetabout the actual columns, just read the data and iterate over however many you have...

filename = 'samplefile.xlsx';
data = xlsread(filename);          % all the numeric data in the file
for i=1:2:size(data,2)             % iterate over columns in steps of two...
  [X,Y]=yourfunction(data(:,i),data(:,i+1)); % call function; pass x, y pair 
  plot(X,Y)                                  % plot the X, Y result or however need 
end

Of course, you'll want to add legend, title, etc., etc., to make plots nice and all, but that's the basics of handling the data.

If there are numeric values prior to the row 14, just set

data(1:NtoKill,:)=[];         % eliminate first NtoKill rows

after reading the sheet or, vice versa,

data=data(RowToKeep:end,:);   % keep rows wanted only

ends up the same either way; take your pick. :)