How to save mat file from specific index

HI, I hope you are doing well.

I have the following Code It saves the frame as mat file name as frame8PSK001 to frame8PSK5000.

I want to save the frame starting from 8PSK5001 to So ON how can i save that

The folllowing for loop is used to save the mat files

for p=1:numFramesPerModType

How can i change the value

dataDirectory='C/NewFolder'
numFramesPerModType=5000
fileNameRoot = "frame";

% Check if data files exist
dataFilesExist = false;
if exist(dataDirectory,'dir')
  files = dir(fullfile(dataDirectory,sprintf("%s*",fileNameRoot)));
  if length(files) == numModulationTypes*numFramesPerModType
    dataFilesExist = true;
  end
end

if ~dataFilesExist
  disp("Generating data and saving in data files...")
  [success,msg,msgID] = mkdir(dataDirectory);
  if ~success
    error(msgID,msg)
  end
  for modType = 1:numModulationTypes
    elapsedTime = seconds(toc);
    elapsedTime.Format = 'hh:mm:ss';
    fprintf('%s - Generating %s frames\n', ...
      elapsedTime, modulationTypes(modType))
    
    label = modulationTypes(modType);
    numSymbols = (numFramesPerModType / sps);
    dataSrc = helperModClassGetSourceAMC(modulationTypes(modType), sps, 2*spf, fs);
    modulator = helperModClassGetModulatorAMC(modulationTypes(modType), sps, fs);
    if contains(char(modulationTypes(modType)), {'B-FM','DSB-AM','SSB-AM'})
      % Analog modulation types use a center frequency of 100 MHz
      channel.CenterFrequency = 100e6;
    else
      % Digital modulation types use a center frequency of 902 MHz
      channel.CenterFrequency = 902e6;
    end
    
    for p=1:numFramesPerModType
      % Generate random data
      x = dataSrc();
      
      % Modulate
      y = modulator(x);
      
      % Pass through independent channels
      rxSamples = channel(y);
      
      % Remove transients from the beginning, trim to size, and normalize
      frame = helperModClassFrameGenerator(rxSamples, spf, spf, transDelay, sps);
      
      % Save data file
      fileName = fullfile(dataDirectory,...
        sprintf("%s%s%03d",fileNameRoot,modulationTypes(modType),p));
      save(fileName,"frame","label")
      
    end
  end
else
  disp("Data files exist. Skip data generation.")
end

[Matt J]

Are you sure that's a good idea? Why not save all frames together in one file? The difficulty you're facing splitting them up will be encountered again when you need to read them back in.

[Med Future]

@Matt J I just want to change the name of the files, The following loop save the frame from 001 to 5000, I just want to save with name 5001 to 10000

for p=1:numFramesPerModType:

fileName = fullfile(dataDirectory,...

sprintf("%s%s%03d",fileNameRoot,modulationTypes(modType),p));

save(fileName,"frame","label")

[Matt J]

Are you sure that's a good idea? Why not save all frames together in one file? The difficulty you're facing splitting them up will be encountered again when you need to read them back in.

[Med Future]

@Matt J My algo takes each frame seperatly thats why

Answer 1

[Matt J]

My algo takes each frame seperatly thats why

That does not disqualify keeping them all in a common .mat file. You can use matfile() to read individual sub-chunks of an array from a .mat file.