Sorting Struct elements in Numerical order

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Md Farhad Mokter 2019-6-6

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https://ww2.mathworks.cn/matlabcentral/answers/465787-sorting-struct-elements-in-numerical-order

评论： Stephen23 2021-5-4

I have a program which takes some pictures in a struct and performs some pixel counting in each of the pictures. After running the program when I see the struct, the elements are not arranged in the way I want them to be. Here is the code-

img_folder = ('C:\Users\mm\work\blackpixelcount');
filenames = dir(fullfile(img_folder,'*.JPG'));
Total_image = numel(filenames);
for i= 1:Total_image
    f = fullfile(img_folder,filenames(i).name);
    im= imread(f);
    bw= imbinarize(im);
    out=nnz(~bw);
    get(i)=out;
    
end 
   

after running the code I see the struct and its sorted as given below-

Now I want the elements to be sorted in numerical ascending order (1,2,3.....9,10,11,12..).

I might be makigs some mistakes there, since I am biggener in matlab. Help will be really appreciated.

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Stephen23 2021-5-4

在 MATLAB Online 中打开

Note that NATSORTFILES now directly sorts the structure returned by DIR:

S = dir(..);
S = natsortfiles(S);

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采纳的回答

KSSV 2019-6-6

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/465787-sorting-struct-elements-in-numerical-order#answer_378081

Use this function from file exchange: https://in.mathworks.com/matlabcentral/fileexchange/47434-natural-order-filename-sort

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Stephen23 2019-6-6

编辑：Stephen23 2019-6-6

"But the 'filenames' variable remained same as before"

Sure. You only define it once (on the second line of your code), nowhere else in your code do you make any changes to filenames. You assigned the output of natsortfiles to variable b, so b contains the sorted filenames.

Follow the examples in the natsortfiles documentation.

Jan 2019-6-6

编辑：Jan 2019-6-6

在 MATLAB Online 中打开

@Md Farhad Mokter: Use this:

img_folder  = ('C:\Users\mm\work\blackpixelcount');
filelist    = dir(fullfile(img_folder,'*.JPG'));
filenames   = {filelist.name};  % added
b           = natsortfiles(filenames);
Total_image = numel(b);
getList     = zeros(1, Total_image);  % Pre-allocate, avoid "get" as name
for i = 1:Total_image
    f  = fullfile(img_folder, b{i});  % not b(i).name
    im = imread(f);
    bw = imbinarize(im);
    getList(i) = nnz(~bw);
end

get is an important Matlab command, so avoid using it as name of a variable.

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更多回答（1 个）

Md Farhad Mokter 2019-6-6

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/465787-sorting-struct-elements-in-numerical-order#answer_378102

在 MATLAB Online 中打开

@Stephen Cobeldick sir,

it worked !!

After reading the documentation part once again, I edited the code in line 3 and line 4.

img_folder = ('C:\Users\mm\work\blackpixelcount');
filenames = dir(fullfile(img_folder,'*.JPG'));
[~,ndx] = natsortfiles({filenames.name});
filenames = filenames(ndx); 
Total_image = numel(filenames);
for i= 1:Total_image
    f = fullfile(img_folder,filenames(i).name);
    im= imread(f);
    bw= imbinarize(im);
    out=nnz(~bw);
    get(i)=out;
    
end 