read multiple csv files from different subfolders

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Jiaqi Wang 2019-10-17

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评论： Image Analyst 2023-10-13

I have a folder, "Raw data", which contains subfolders for subjects 005 - 016. In each subfolder, I want to choose a subsubfolder, "A". In "A" folder, there are 23 .csv files. How can I read them as individual file (without merging them) at once, maybe using a loop function of other methods?

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Answer 1

Four Eyes 2023-10-13

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编辑：Four Eyes 2023-10-13

This might be coming in too late. But I recently ran accross a similar problem and here is what that worked for me. Hopefully it is useful to someone!

Suppose you have Fodler 1 stored somewhere like C:\Users\username...\Folder1\....

And You have multiple subfolders like this:

C:\Users\username...\Folder1\Subfolder1\Random_name1.csv; C:\Users\username...\Folder1\Subfolder1\Random_name2.csv;

C:\Users\username...\Folder1\Subfolder2\Random_name3.csv; C:\Users\username...\Folder1\Subfolder2\Random_name4.csv;

and so on

%To read all the file names, do this:

location = C:\Users\username...\Folder1\**\;

files= dir([location '*.csv'])

%To read the data and store in a matrx, do this:

for ii = 1:length(files)

data(:,:,ii) = readmatrix([files(ii).folder '\' files(ii).name]);

end

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Image Analyst 2023-10-13

在 MATLAB Online 中打开

That's similar to what's in the FAQ: https://matlab.fandom.com/wiki/FAQ#How_can_I_process_a_sequence_of_files?

but for robustness you should use fullfile to construct the file pattern and filename.

% To read all the file names, do this:
location = "C:\Users\username...\Folder1\**\";
filePattern = fullfile(location, "*.csv")
files = dir(filePattern)
% To read the data and store in a 3-D array, do this:
% (NOTE: all data must be the same size 2-D matrix).
for ii = 1 : length(files)
    fullFileName = fullfile(files(ii).folder, files(ii).name);
    fprintf('Processing %d of %d : "%s".\n' ii, numel(files), fullFileName)
    data(:,:,ii) = readmatrix(fullFileName);
end

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Answer 2

prasanth s 2019-10-17

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编辑：prasanth s 2022-12-14

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Use 'dir' function to get the directory and file list of any folder. e.g

D=dir('Raw data');

output 'D' is an structure array contains all foldernames.

use following code to get all csv filenames

A=dir('myfolder\*.csv');

get the filenames from 'A' and

use 'csvread' function to read each csv files

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Answer 3

Image Analyst 2022-12-14

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Try this:

% Specify top level folder and file pattern.
topLevelFolder = pwd; % Or whatever you want.
filePattern = fullfile(topLevelFolder, '*.csv')
% Get a list of all files in that folder and within its subfolders.
ds = fileDatastore(filePattern, 'ReadFcn', @readmatrix)
allFileNames = ds.Files