Size in byte of file reduced when i combine two csv

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shery khan 2022-7-3

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1752495-size-in-byte-of-file-reduced-when-i-combine-two-csv

评论： Stephen23 2022-7-3

Here is code that can first check the length of file if it is less then 800 it will do following steps first it will get the data from 1-600 rows in a Variable then using same csv it will get 1-200 rows in a Variable save both variable in new files and at the end combine them but issue is that my file size in byte is reduced when ever i check the data in cell i observe that values are truncated. can any one have another logic for this work

home_dir = 'D:\DS\Testing';
sensors = dir(home_dir);
for sens =3:length(sensors)
    classes = dir(fullfile(home_dir, sensors(sens).name));
    for cls=3:length(classes)
        data = dir(fullfile(home_dir, sensors(sens).name, classes(cls).name));
        toWrite = cell(zeros(1,1));
        for dat = 3:length(data)
            
            tmp = readtable(fullfile(home_dir, sensors(sens).name, classes(cls).name, data(dat).name));
            
     
             n_rows_target = 800;
             n_rows = size(tmp,1);  
            if n_rows < n_rows_target % Check the file length
                
                
                B=tmp(1:600,1:end);  %Get the data from 1-600 rows 1-4 Columns
                C=tmp(1:200,1:end);  % Get the data from 1-200 rows 1-4 Columns same file 
                
                
                writetable(B, 'new.csv');  % File is created in which 1-600 rows exist
                writetable(C,'Two.csv');   % File is created in which 1-200 rows chunk 
                
                csv1 = readmatrix('new.csv'); % Reading Files
                csv2 = readmatrix('Two.csv');
                allCsv = [csv1;csv2]; % Concatenate vertically means 1-600 
                                      %                              1-200
                                      %                              800
                                      %                              Rows
                
                writematrix(allCsv, strcat(strrep(data(dat).name, ' ', '_'), '')); % New File is created with 800 rows
            end
        end
    end
end   

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Stephen23 2022-7-3

在 MATLAB Online 中打开

As an aside, note that these lines of code:

sensors = dir(home_dir);
for sens =3:length(sensors)

are a buggy attempt to deal with the dot directory names. Robust code uses SETDIFF or ISMEMBER.

https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-fscc/fccd0313-0364-45bd-b75c-924fd6a5662f

https://www.mathworks.com/matlabcentral/answers/484430-using-struct-dir-selpath-what-do-and-mean-as-struct-name#answer_395754

https://www.mathworks.com/matlabcentral/answers/40949-omitting-pointers-when-listing-folder-contents#answer_50568

https://www.mathworks.com/matlabcentral/answers/13978-list-of-files-sorting#answer_19278

As Walter Roberson wrote in that last link: "In short: if your code assumes that '.' and '..' are the first two entries in a directory, your code has a bug (even in MS Windows). If your code assumes that directory entries are returned in any sorted order, your code has a bug (in all OS.)"

"when ever i check the data in cell i observe that values are truncated"

Nothing in your code seems to "truncate" values. Please upload two sample files by clicking the paperclip button.

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