Random draw without re-delivery in a loop

Hi all,

I have to create a loop in which I have to pick 5 images without resetting at each turn.

For the randomization I did this :

randomizedTrials_neutral = randperm(nTrials_neutral_run,5)

But I don't know how to insert it in a loop to randomly pick out 5 images without resetting at each turn.

Would you know how I can do this, please?

Thanks for your help

Answer 1

[Jan]

What are your input data? A list of files stored in a folder? (As usual: please explain this instead of letting the readers guess the details.) Then:

List  = dir(fullfile('C:\Your\Folder', '*.jpg'));
File  = fullfile({List.folder}, {List.Name});
Index = 1:numel(File);
for k = 1:numel(File) / 5
    selected = randperm(numel(Index), 5);  % Select 5 of the existing images
    fprintf('Round %d:\n', k);             % Show them (or do whatever you need)
    fprintf('  %s\n', File(Index(selected)));
    Index(selected) = [];                  % Remove selected images from the list
end

Another simple approach:

List  = dir(fullfile('C:\Your\Folder', '*.jpg'));
File  = fullfile({List.folder}, {List.Name});
Index = randperm(numel(File));
Blocks = reshape(Index, 5, []);  % Assuming than #files is multiple of 5
% Now the column vector Blocks(:, k) contains the indices of 5 randomly selected images.

for k = 1:size(Blocks, 2)
    fprintf(' %d', Blocks(:, k));
    fprintf('\n');
end

[Pamela Pindi]

Thanks for your answer !

My input data are a list of 60 images into a folder