How to randomly extract 50 images from a file?

Hello!

I am new to Matlab, so please bear with me. I have a file containing thousands of images. I am trying to randomly select 50 images and save it into a new file.

This is the code im trying to use.

Dest     = '/Users/Desktop/Image Dataset';
FileList = '/Users/Downloads/ILSVRC2012_img_val';
Index    = randperm(50, numel(FileList));
for k = 1:50
  Source = FileList(Index(k)).name;
  copyfile(Source, Dest);
end

But I keep getting error "Dot indexing is not supported for variables of this type". How do i fix this?

Thank you!

Answer 1

[Jan]

Dest     = '/Users/Desktop/Image Dataset';
FileList = dir('/Users/Downloads/ILSVRC2012_img_val/*.jpg');  % DIR command was missing
                                                              % and perhaps
                                                              % the pattern
Index    = randperm(numel(FileList), 50);  % Swap order of arguments
for k = 1:50
  Source = FileList(Index(k)).name;
  copyfile(Source, Dest);
end

[AK]

Thank you! this helped.

I made the changes you suggested. However, now i recieve the error " error using copyfile. arguement must be text scalar"

Do you know what i could be doing wrong here? Thanks!

[Jan]

Use the debugger to find out, what the variable is. Type this in the command window:

dbstop if error

Then run the code. When Matlab stops at the error, check the arguments of COPYFILE:

class(Source)
size(Source)
class(Dest)
size(Dest)