how to read sequence of files that are seemingly random

I am trying to read 1000+ files with the following filename format: myPos_HH_MM_SS_SSS.mat. There seems to be no pattern for HH_MM_SS_SSS. How do I perform this?

Answer 1

[dpb]

d=dir(fullfile('YourBaseDirectory','myPos_*.mat');
for i=1:length(d)
  load d((i).name
  ...
  % Do what ever needs done with variables in the .mat file here
  ...
end

will process in alphabetical order. If need in chronological order then

d=dir(fullfile('YourBaseDirectory','myPos_*.mat');
dn=[dn(:).datenum].';          % get the datenums for each file
[~,ix]=sort(dn);               % and sort ascending, save order index
d=d(ix);                       % rearrange the directory struct order

From here on, everything's the same...

for i=1:length(d)
  load d((i).name

[cgo]

sorry I am so confused by this. So I do not need any further sorting, just reading my files, doing something to them and saving them in another way.

I am confused by the order you presented.

[dpb]

Well, it wasn't clear whether the "seemingly random" phrase was a plea for order or only one for just how to access if didn't necessarily know the exact name for every one...Free extra service, if you will! :)

Unfortunately, when I copied the initial code to make the second example if order were to be important, I didn't realize that I had elided it from the first loop...that did leave some confusion, granted.

[Image Analyst]

cgo, that's what I did. Did you see my answer below? No sorting, just going through your mat files one-by-one just as dir() gives them to you.

[dpb]

Which I re-edited to put back what I inadvertently deleted... :)

Answer 2

[Image Analyst]

You did not ask for any sorting (not sure why others are sorting). You simply asked how to read files that have random names, not a sequence in any particular alphanumeric order. So that means you can simply use dir('*.mat') to read the files, as per the FAQ: https://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

% Specify the folder where the files live.
myFolder = pwd; % or wherever;
% Check to make sure that folder actually exists.  Warn user if it doesn't.
if ~isdir(myFolder)
  errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
  uiwait(warndlg(errorMessage));
  return;
end
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(myFolder, '*.mat'); % Change to whatever pattern you need.
theFiles = dir(filePattern);
numberOfFiles = length(theFiles);
fprintf('Found %d .mat files in folder: "%s".\n', numberOfFiles, myFolder);
for k = 1 : numberOfFiles
  baseFileName = theFiles(k).name;
  fullFileName = fullfile(myFolder, baseFileName);
  fprintf(1, 'Now loading %s\n', fullFileName);
  % Now "read" (load) the mat file.  Returned value will be a structure.
  s = load(fullFileName)
  % Now do whatever you want with s.
end