file read by number and perform operation

Dear all,

from a list of txt(ascii) file text0, text1, text2, text3, text4, ... which is an alternace of data and background measurements.

I would like to subtract file by pairs:

1 - 0, 
3 - 2, 
5 - 4, 
7 - 6
... etc.

All files are located into 1 folder, so my first attempt was as follow:

myFolder = 'C:\Users\...........';
filePattern = fullfile(myFolder, '*.txt')
theFiles = dir(filePattern);
for k = 1 : length(theFiles)
        datafile1 = theFiles(k).name;
        fullFileName = fullfile(myFolder, datafile1);
        fprintf(1, 'Now reading %s\ data n ', fullFileName);
        rawdata = dlmread(fullFileName,'\t','C4..AYP4');

          a = k + 1;
          datafile2 = theFiles(a).name;
          backgroundfile = fullfile(myFolder, datafile2);
          xaxis = dlmread(backgroundfile,'\t','C2..AYP2');
          background = dlmread(backgroundfile,'\t','C4..AYP4');
          fprintf(1, 'Now reading %s background \n', backgroundfile);

          % do whatever with data       
          C = bsxfun(@minus, rawdata, background);
  end

files are liste in a structure as expected with their names, however, as you can see the problem is that the loop will not do the subration by pair (1-0, then 3-2, 5-4, etc.)

in fact i got something like this:

(process of 0 data) minus (process of 1 background), then (process of 1 data)minus (process of 2 background), etc.

how should I correct the loop to work by pair of file properly ?

Thank you for your time,

Answer 1

[Walter Roberson]

If you change

fprintf(1, 'Now reading %s\n', fullFileName);

to

fprintf(1, 'Now reading %s for foreground\n', fullFileName);

and

fprintf(1, 'Now reading %s\n', backgroundfile);

to

fprintf(1, 'Now reading %s for background\n', backgroundfile);

then I think you will find that you are reading the files the way you asked.

[Taro Ichimura]

Dear Walter,

Thank you, I think there is a small understanding, what I need is that the operation within loop (the Bsfun for subtraction of file) is done by pair of file as follow: background(file1)-data(file0), then background (file3) - data (file2), etc... (by pair). AND NOT (1-0, 2-1,3-2, etc.) as does the present loop.

[Walter Roberson]

Just reverse the order then

myFolder = 'C:\Users\...........';
filePattern = fullfile(myFolder, '*.txt')
theFiles = dir(filePattern);
for k = 1 : length(theFiles)
        datafile1 = theFiles(k).name;
        backgroundfile = fullfile(myFolder, datafile1);
        fprintf(1, 'Now reading %s\ background n ', );
        background = dlmread(backgroundfile,'\t','C4..AYP4');

            a = k + 1;
            datafile2 = theFiles(a).name;
            fullFileName = fullfile(myFolder, datafile2);
            xaxis = dlmread(fullFileName,'\t','C2..AYP2');
            rawdata =  dlmread(fullFileName,'\t','C4..AYP4');
            fprintf(1, 'Now reading %s data \n', backgroundfile);

            % do whatever with data       
            C = bsxfun(@minus, rawdata, background);
    end

[Walter Roberson]

You can use

for k = 1 : 2 : length(theFiles)