How to read and plot the data from csv files of subfolders?

Question

muhammad choudhry 2022-3-9

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1667989-how-to-read-and-plot-the-data-from-csv-files-of-subfolders

评论： Walter Roberson 2022-3-10

Hi,

I am trying to read the csv files from the 48 subfolders and plot the data from each folder csv file onto the graph but it is only plotting the data from one file. I am not sure where I am going wrong? can anyone help? Below is the code.

Code:

files = subdir('F:\3-PIV_Experimental_Data\Outlet_110\Data_LaserSheet_D\Data_PIV\5-AverageFilter_VelocitiesExtration\Point_Velocities\Uy\*.csv');
for i = 1:numel(files)
    filename = files(i).name;
    data = readmatrix(filename);
    Uy=data(1,2);
    time = data(1,1);
    plot(time,Uy,'*')
end

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Answer 1

Walter Roberson 2022-3-9

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1667989-how-to-read-and-plot-the-data-from-csv-files-of-subfolders#answer_914134

编辑：Walter Roberson 2022-3-9

projectdir = 'F:\3-PIV_Experimental_Data\Outlet_110\Data_LaserSheet_D\Data_PIV\5-AverageFilter_VelocitiesExtration\Point_Velocities';
files = dir( fullfile(projectdir, '*', '*.csv') );
filenames = fullfile({files.folder}, {files.name});
num_files = length(filenames);
all_Uy = zeros(num_files,1);
all_time = zeros(num_files,1);
for i = 1:numel(files)
    filename = filenames{i};
    data = readmatrix(filename);
    all_Uy(i) = data(1,2);
    all_time(i) = data(1,1);
end
scatter(all_time, all_Uy, '*');

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muhammad choudhry 2022-3-10

what was I doing wrong?

Walter Roberson 2022-3-10

Were you using subdir() from the File Exchange? https://www.mathworks.com/matlabcentral/fileexchange/15859-subdir-a-recursive-file-search

If so then the equivalent would be

files = dir( fullfile(projectdir, '**', '*.csv') );

Anyhow, the error was that you were only pulling out the file name from the directory information, without pulling out information about which directory the file was in.

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