How to save variable after every trials so that it stores different values for each of the different trials without getting overwriiten values

In the below chunk of code, how can i save 'Current_file' variable after every trial, so that it stores 70 values for each of the 70 trials. There are total 70 number of trials and 161 images in Manipulable folder. Kindly refer to the full code attached here. Any help would be highly appreciated. Thank You.

folder ='F:\Ankit\2nd Study_Jan_2023\Manipulable_objects'

manipulable_image = dir(fullfile(folder, '/*.bmp'))

as = numel(manipulable_image);

imageseq = randperm(as);

for i=1:as

idx =imageseq(i);

img = imread(fullfile(folder,manipulable_image(idx).name));

Current_file = fullfile(folder,manipulable_image(idx).name);

end

[Stephen23]

"how can i save 'Current_file' variable after every trial, so that it stores 70 values for each of the 70 trials."

The simple and efficient MATLAB approach is to use indexing, e.g. into a cell array:

https://www.mathworks.com/help/matlab/import_export/process-a-sequence-of-files.html

But really this question is simpyl answered by the fact that you don't need to do anything: all of the filenames are already stored in the structure returned by DIR(), so why do you need to duplicate that data for no obvious benefit?

[ANKIT MAURYA]

I think the structutre DIR() stores all the 161 images present in the Manipulable_objects named folder , but the 'Current_file' variable should store only 70 random images out of 161 total images. I want 'Current_file' variable to store 70 random images which is getting presented on 70 different trials (i_trial = 1:70) i.e each random image out of 161 images on each of the 70 trials

[Stephen23]

"I think the structutre DIR() stores all the 161 images in the Manipulable_objects named folder , but the 'Current_file' variable should store only 70 random images out of 161 total images."

Nothing in your code seems to select 70 filenames.

In any case, you can simply perform that selection on the structure returned by DIR():

k = 70;
S = dir(..)
X = randperm(numel(S),k)
T = S(X)

Or indeed, make that exact same selection after the loop. Why make your code more complex?

[ANKIT MAURYA]

In your code------ variable 'T' is storing 70 random images if the value of 'k' is 70 , right ?

If this is the case, now i want to know, out of these 70 images stored in T, which of the image is presented on which of the trial (for i_trial =1:70). How can i do so ?

[Stephen23]

"In your code------ variable 'T' is storing 70 random images if the value of 'k' is 70 , right ?"

It stores the filenames in T, not the images.

If you make k==70 then RANDPERM will randomly select 70 of the images from that folder.

"out of these 70 images stored in T, which of the image is presented on which of the trial (for i_trial =1:70)."

I have no idea, becase nowhere in your question do you explain how a "trial" is represented or indicated or encoded.

[ANKIT MAURYA]

Hi stephen,

Thank you for explaining first two questions clearly.

The third question---

"out of these 70 images stored in T, which of the image is presented on which of the trial (for i_trial =1:70)."

I have no idea, becase nowhere in your question do you explain how a "trial" is represented or indicated or encoded.

I have attached the whole program initially when i asked the question.

I am attaching again here for your perusal

Answer 1

[MFK]

You can use save Current_file variable after it completetly created with save(filename,variable) function.

https://www.mathworks.com/help/matlab/ref/save.html#d124e1343125

And also you can use it with eval function to save with variable variables names like Current_file_iter1,Current_file_iter2,Current_file_iter3 ....

For this use

for i=1:i_trial

%%%%%%

%%%%%%

Current_file = fullfile(folder,manipulable_image(idx).name);

filename=sprintf('Current_file_iter%d',i_trial);

save(filename,"Current_file");

end

[Stephen23]

"And also you can use it with eval function to save with variable variables names like Current_file_iter1,Current_file_iter2,Current_file_iter3 ...."

Best avoided: https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

Answer 2

[ANKIT MAURYA]

Hi MFK,

Can i directly copy and paste this (below) chunk of code in my program without adding/deleting anything ?

And if yes, then where should I paste, i mean at what location in my program?

for i=1:i_trial

%%%%%%

%%%%%%

Current_file = fullfile(folder,manipulable_image(idx).name);

filename=sprintf('Current_file_iter%d',i_trial);

save(filename,"Current_file");

end

[MFK]

filename=sprintf('Current_file_iter%d',i_trial); save(filename,"Current_file");

Pastr this before end try it for one iteration. It will probably work.

[ANKIT MAURYA]

filename=sprintf('Current_file_iter%d',i_trial);

save(filename,"Current_file");

end

It is already pasted before end, isn't it? or I am wrong to get what you are saying? Kindly clarify me. Thank You.

[MFK]

folder ='F:\Ankit\2nd Study_Jan_2023\Manipulable_objects'
manipulable_image = dir(fullfile(folder, '/*.bmp'))
as = numel(manipulable_image);
imageseq = randperm(as);
for  i=1:as
    idx =imageseq(i);
    img = imread(fullfile(folder,manipulable_image(idx).name));
    Current_file = fullfile(folder,manipulable_image(idx).name);
    filename=sprintf('Current_file_iter%d',i); %%% this is the code I suggest
    save(filename,"Current_file"); %%% this is the code I suggest
end

You can use like that.

If you want to save in every iteration you can use like that. But if you want to save after all iterations completed. You can use a struct like;

folder ='F:\Ankit\2nd Study_Jan_2023\Manipulable_objects'
manipulable_image = dir(fullfile(folder, '/*.bmp'))
as = numel(manipulable_image);
imageseq = randperm(as);
for  i=1:as
    idx =imageseq(i);
    img = imread(fullfile(folder,manipulable_image(idx).name));
    Current_file{i,1} = fullfile(folder,manipulable_image(idx).name); %%% this is the code I suggest
end
save(Current_file,"Current_file"); %%% this is the code I suggest