loading multiple csv files using readmatrix

Question

julian gaviria 2023-10-19

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2035849-loading-multiple-csv-files-using-readmatrix

编辑： Stephen23 2023-10-19

How can I load to matlab workspace multiple matrices with the same dimension located in individual csv files? They have different file names with the same extension (.csv)

Expected variable in workspace: A 3D matrix.

I have tried something like

Folder = 'C:\My\Folder';';
for k = 1 :100
   filename = fullfile(Folder, sprintf('%d.csv', k));
   data     = readmatrix(filename);
   ...
end

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Dyuman Joshi 2023-10-19

@julian gaviria, Does the folder containing the csv files have any other files than the ones to be read?

julian gaviria 2023-10-19

@Dyuman Joshi, no. there is only 1 sheet per .csv file. All the .csv files contain a 2D matrix with the same dimension

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Answer 1

Stephen23 2023-10-19

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2035849-loading-multiple-csv-files-using-readmatrix#answer_1336719

在 MATLAB Online 中打开

Use DIR:

P = 'C:\My\Folder';
S = dir(fullfile(P,'*.csv'));
for k = 1:numel(S)
    F = fullfile(P,S(k).name);
    S(k).data = readmatrix(F);
end

All of the imported file data are stored in the structure S. For example, the 2nd file:

S(2).name % filename
S(2).data % file data

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julian gaviria 2023-10-19

Thanks @Stephen23

How can I arrange all the content of "S(2).data" in a 3D array?

Stephen23 2023-10-19

编辑：Stephen23 2023-10-19

在 MATLAB Online 中打开

"How can I arrange all the content of "S(2).data" in a 3D array? "

A = cat(3,S.data)

https://www.mathworks.com/help/matlab/matlab_prog/access-multiple-elements-of-a-nonscalar-struct-array.html

https://www.mathworks.com/matlabcentral/answers/1656435-tutorial-comma-separated-lists-and-how-to-use-them

But note that the order of the files will be that returned by DIR, which might not be the order you expect. If you require the filenames in alpha-numerical order then you will have to sort S yourself, e.g. by downloading NATSORTFILES:

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

https://www.mathworks.com/matlabcentral/fileexchange/47434-natural-order-filename-sort

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Answer 2

Sulaymon Eshkabilov 2023-10-19

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2035849-loading-multiple-csv-files-using-readmatrix#answer_1336714

在 MATLAB Online 中打开

Here is how you can create such a code:

Folder = 'C:\Users\...';
F_Pat = fullfile(Folder, '*.csv');
FILES = dir(F_Pat);
F_Names={FILES.name};
for k = 1 :length(F_Names)
    Get_FName = FILES(k).name;
    F_FileName=fullfile(FILES(k).folder, Get_FName);
    data{k}= readmatrix(F_FileName);
    ...
end

All the best

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Sulaymon Eshkabilov 2023-10-19

My proposed code works for any file names not necessary file names should be sequential. All collected data in a cell array that can be also altered to store read data as a structure or stacked data of arrays, etc.

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