exporting strings out of structure into a vector

Hello MatlabCentral-community,

I have a structure(1*k). For k images there is one time data. Now, I want to generate a vector (for each image one time data). But unfortunately, I'm struggling with this task.

I tried it by:

[filename, pathname] = uigetfile('C:\Users\Pictures\Cam\*.jpg', ...
                                 'Select Pictures for processing',...
                                 'Multiselect','on');
 nop = length(filename);   % number of pictures
 for  k = 1:nop
     n = num2str(k);
     info_all = imfinfo(fullfile(pathname, filename{k}));
 end
 Img_info(k) = info_all;
 % until here it works (getting one single string)
 timeinfo_single = Img_info.FileModDate   
 timevector(k) = Img_info(k).FileModDate

I would be very happy, if somebody could put me on the right track,

greetings,

Gemma

Answer 1

[Guillaume]

As per Nobel's answer, you end you loop prematurely, the end should be in the last line.

it still won't work though as you can't put several strings (FileModDate) into a matrix, you have to use a cell array. Therefore, the end of your program should read:

     timevector{k} = Img_Info(k).FileModDate;
  end

Unless you meant to put a datenum in your timevector, in which case:

     timevector(k) = datenum(Img_info(k).FileModDate);
  end

By the way, I find your choice of variable name confusing. info_all is the information of a single image and Img_Info is the info of all images.

Finally, the way I would have written the same code would have been with just these three lines:

[filename, pathname] = uigetfile('C:\Users\Pictures\Cam\*.jpg', ...
                               'Select Pictures for processing',...
                               'Multiselect','on');
Img_Info = cellfun(@(fname) imfinfo(fullfile(pathname, fname)), filename);
timevector = datenum({Img_Info.FileModDate});

Answer 2

[Nobel Mondal]

Your Img_info variable is storing only the information of the last (nop-th) image, since it is outside the for loop.

Answer 3

[Gemma]

Thank you both very much! Now it works and is furthermore elegant!

I still tend to write rather cumbersome.