How to open multiple text files and populating matrices with the data

I have written the following codes to open a text file and populate a matrix with the data. It works fine.

fid=fopen('01_06_13hi.txt'); %Opens the file
allData =[]; %Creats a matrix to store all data
n = 0;
while feof(fid)== 0;
    d1 = fgetl(fid);  % reading the file line by line
    if strfind(d1,'-NaN') %Overrules the 'Not a Number' value
    else   
        n=n+1;
        ind= find(d1(:)==':'); %finds ':' in the data string and storing in variable 'ind'
        ind2 = find(d1(:)=='/'); %finds '/' in the data string and storing in variable 'ind2'
        d1(ind) = ' '; %string data
        d1(ind2) = ' '; %string data
        d2 = str2num(d1); % converting the data from string to number
        allData(n,:) = d2; %Storing data of d2
    end
end

Now I have some 630 .txt files. I have tried to modify the the code as follows:

filesFolder = 'lo_hi1/';
allTextFiles = dir([filesFolder,'*.txt']);
numberOfTextFiles = numel(allTextFiles);
nameOfTextFiles = {allTextFiles.name};
allData =[];
n = 0;
for i=1:numberOfTextFiles
    fileID=fopen(nameOfTextFiles{i});
      while feof(fileID)== 0;
          d1 = fgetl(fileID);
          if strfind(d1,'-NaN')
          else
              n=n+1;
              ind= find(d1(:)==':');
              ind2 = find(d1(:)=='/');
              d1(ind) = ' ';
              d1(ind2) = ' ';
              d2 = str2num(d1);
              allData(n,:) = d2;
          end
      end
      fclose(fileID); %closing the file
end

I expected it to work but unfortunately it is not working. The command window showed the following:

Error using feof Invalid file identifier. Use fopen to generate a valid file identifier.

Error in multifileload (line 15) while feof(fileID)== 0;

Can anyone help me out?

[dpb]

Well, what does "not working" mean, precisely? We don't have your data so can't run it and can't see your terminal from here, either...

[Md. Golam Mostafa]

Oh, sorry, I did not foresee the situation prevailing at your end. The command window showed the following:

Error using feof Invalid file identifier. Use fopen to generate a valid file identifier.

Error in multifileload (line 15) while feof(fileID)== 0;

Answer 1

[Walter Roberson]

      fileID = fopen( fullfile(filesFolder, nameOfTextFiles{i}));

[Md. Golam Mostafa]

Thanks, it worked. I have 630 txt files. Can you suggest me easy way to store data in 630 different matrices?