Variable in a string name

I am reading columns of binary files to plot. I have all my files in one folder and I want to plot them and pull out certain data. How can I set up a loop that will go through all the files?

My idea so far:

1) Use D= dir('W:\Folder')

to retrieve the names of all the files

2) for i= 1:70

str = ('W:\Folder\D(i)\Data')

fid = fopen(str);

How can I insert the different names in the array D from step 1?

I tried sprintf but I believe there is a problem because it's a path.

Thank you for your help

Answer 1

[Geoff Hayes]

Andrew - try using fullfile instead

 foldername = 'W:\folder';
 files      = dir(foldername);

 for k=1:length(files)

    % ignore directories
    if ~files(k).isdir
         % build the file name
         filename = fullfile(foldername,files(k).name);

         % open the file
         fid = fopen(filename);

         if fid>0

             % do stuff with file contents

             % close the file
             fclose(fid);
         end

    end
 end

You can use sprintf as well (something like str = sprintf('W:\folder\%s\,files(k).name)' but the above should work just as well.

[Image Analyst]

Very robust. But after looking at his question again, I think he want to use dir() to get directories rather than files . Why do I think that? Because D(i) is in the middle of "W:\Folder\D(i)\Data" so he intends D(i) to be a folder name. So I think he wants all the subfolders of "Folder" and Data are files inside the subfolders, and unfortunately Data may not have any extension to the filename. SO maybe "if ~files(k).isdir" should actually be "if files(k).isdir"

[Andrew]

Thank you, I was able to work it out using fullfile

Answer 2

[Image Analyst]

Use sprintf() to construct the filename from i.

filename = sprintf('W:/Folder/%s/Data.dat', D(i).name);

See the FAQ for full sample code: http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F