How to address files that are starting with certain word

Dear All,

In my main directory I do have 5 subdirectories(named 1,2,3,4 and 5) in all of which there is only one file whose name starts with 'word.' . (After . there is a 5-digit number)

I have written a code on the parent directory which goes into each subdirectories in the order. In each subdirectory I need to fopen the file whose name starts with 'word.', what should I do? Since I do not have any idea about the 5 digit number coming with the name of the file, I cannot use sprintf. Do you have any idea how I can do it?

If the 5-digit number was known then it was really simple as:

   input =  sprintf('%s%d','REAX.o',12345);
   fid = fopen (input, 'r');

But now it is confusing to me.

Thank you so much

Answer 1

[Jan]

FileList = dir(fullfile(Folder, 'word.*'));
FileName = fullfile(folder, FileList(1).name));
fid = fopen(FileName);
...

You will find a lot of submissions in the FileExchange, which find files recursively in subfolders.

[Homayoon]

Thank you, I know about getting into the subfolders. I wonder if I can use something as

   input =  sprintf('%s%d','REAX.o',*);

which I think I cannot!!! With respect Jan, I guess I did not get my answer. Can you kindly elaborate on it ?

[Image Analyst]

No, because input is a reserved built-in function name. But you can do

baseFileName =  sprintf('REAX.o%d', yourNumber);
fullFileName = fullfile(yourFolder, baseFileName);

See the FAQ for Jan's method and another slightly different one: THE FAQ

[Homayoon]

Thanks but as I said in the question, I do not know what the number is. I just know there is a file whose name starts with 'REAX.o'. I do not have any clue what the number could be. And I need to fopen the mentioned file in each subfolder

[Stephen23]

@Homayoon: then why not simply use Jan Simon's Answer, which does exactly what you want. It does not require that you know the number. It uses dir. Do you understand how dir works? Do you see that it does not use sprintf? Why are you complaining about sprintf when this answer does not use sprintf?

Perhaps this makes that answer a bit clearer for you:

C = CellArrayOfSubFolders
for k = 1:numel(C)
    FileList = dir(fullfile(C{k}, 'word.*'));
    FileName = fullfile(Folder, FileList(1).name));
    fid = fopen(FileName,'rt');
    ... whatever you do with fid
    fclose(fid);
end

[Homayoon]

It did not work Stephen. I received tons of errors.

[Homayoon]

For whatever reason C{k} seemed to be wrong since C is defined as an array. Secondly, I do not know what the folder is in your code Stephen?!

[Stephen23]

• Folder is a string of the path to the folder where the subfolders are located. This may be the current directory.
• CellArrayOfSubFolders is a cell array of subfolder names (strings).

That is all you need to supply. C should not be a numeric or char array. Please tell us the complete error message and the complete code that you are using.

[Jan]

@Homayoon: How can you get "a ton of errors", when Matlab stops at the 1st error already?

The code I've posted, especially the dir command, searchs in the specified folder for a file, which starts with "word." and anything following. This fails, if you have the wanted file called "word.12345" and another file is called "word.abcde", because both files are selected by the pattern "word.*". But if "word." specifies the file uniquely, the code I've posted gets its file name reliably.

[Homayoon]

I figured it out and this was something that I was looking for: (I had to use sprintf for some reasons)

      foldername = sprintf('C:\\Users\\h\\h\\Tt\\Actual Analysis\\BI\\reverse-input\\New folder\\9\\%d',C(1,k));
    cd(foldername);
    filelist = dir(fullfile( 'REAX.o*'));
    filelist(1).name;
    out = sprintf ('C:\\Users\\h\\h\\Tt\\Actual Analysis\\BI\\reverse-input\\New folder\\9\\%d\\%s', C(1,k) ,filelist(1).name);

    fid = fopen(out,'rt');

[Jan]

Sorry, Homayoon, this is a blind guessing.

• You do not have to insert double slashes only to remove them using sprintf:

foldername = fullfile( ...
  'C:\Users\h\h\Tt\Actual Analysis\BI\reverse-input\New folder\9\', ...
   sprintf(%d', C(1,k)));
filelist = dir(fullfile(foldername, 'REAX.o*'));
out = fullfile(foldername, filelist(1).name);

• Omit the "cd(foldername);", but use absolute file names only.
• Omit the useless line "filelist(1).name;"

And now this is equivalent to the code I've posted. Voilà.