Read line-by-line matrix NaN how to delete search?

Hi, I have many text files.Read them, one by one, each line check whether NaN string destroyed in a need to re-create a new matrix.

files = dir('C:\myfolder\*.txt');
for k=1:2
  fid=fopen(files(k).name);
  tline = fgetl(fid);
  while ischar(tline)
       %     disp(tline);
       B=[];
       B=[B tline];
       tline = fgetl(fid);
  end
  fclose(fid);
end

[Jan]

What exactly is your question? Where do the NaNs appear? How do the files look like? What is the wanted output?