exporting strings out of structure into a vector

Question

Gemma 2015-4-30

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/214442-exporting-strings-out-of-structure-into-a-vector

回答： Gemma 2015-5-2

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

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Answer 1

Guillaume 2015-4-30

2
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在 MATLAB Online 中打开

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});