How to load txt files from subfolders

Question

Alexandr Lozak 2018-7-9

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/409443-how-to-load-txt-files-from-subfolders

评论： Alexandr Lozak 2018-7-12

There is error as i am trying to load .txt files from subfolders. How can i load all *.txt files using generated function (imptxt(FileName,startRow,endRow))

if true
Files=dir('**/*AVE*.txt'); % looking for txt files with 'AVE' at the beginning
for k=1:length(Files)      % k=46
 FileNames=Files(k).name
end
ImpFiles=zeros(k,100000);
for i=1:k
    ImpFiles(i,:)=imptxt(Files(i).name,1,1); % loading all files in one array using generated function for import
end

and i have such error:

    if true
Error using textscan
Invalid file identifier. Use fopen to generate a valid file identifier.
     if true
Error in imptxt (line 100034)
dataArray = textscan(fileID, formatSpec, endRow(1)-startRow(1)+1, 'Delimiter', delimiter, 'TextType', 'string', 'EmptyValue', NaN,
  'HeaderLines', startRow(1)-1, 'ReturnOnError', false, 'EndOfLine', '\r\n');
Error in BN (line 17)
ImpFiles(k,:)=imptxt(Files(k).name,1,1);
 % code
end

UPD. I checked and it working but only if i start it inside one of subfolders. Otherwise it shows same error as above

8 个评论
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Jan 2018-7-12

编辑：Jan 2018-7-12

在 MATLAB Online 中打开

This loop is useless:

for k=1:length(Files)
   FileNames=Files(k).name
end

It overwrites FileNames repeatedly.

I'm convinced that the M-file imptxt with more than 100'000 lines of code is rubbish. Which tool did create this function? In any case, something went wrong. I recommend to start from scratch again and create a better tool for importing.

Alexandr Lozak 2018-7-12

在 MATLAB Online 中打开

I used Matlabs deafault import tool. 100 000 comes from number of values in my .txt files. biggest part of function code looks like this:

%%Format for each line of text:
%   column1: double (%f)
...
%   column100000: double (%f)

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Answer 1

Jan 2018-7-12

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/409443-how-to-load-txt-files-from-subfolders#answer_328554

编辑：Jan 2018-7-12

在 MATLAB Online 中打开

Files = dir('**/AVE*.txt');
for k = 1:length(Files)
   FileName      = fullfile(Files(k).folder, Files(k).name);
   ImpFiles(k,:) = dlmread(FileName);
end

It is smarter to run the code in backward direction:

for k = length(Files):-1:1

Then ImpFiles has the correct size in the first iteration and Matlab does not waste time with the iterative growing of the array.

1 个评论
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Alexandr Lozak 2018-7-12

Thank you for answer and explanation

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Answer 2

Alexandr Lozak 2018-7-12

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/409443-how-to-load-txt-files-from-subfolders#answer_328544

编辑：Alexandr Lozak 2018-7-12

在 MATLAB Online 中打开

 This code worked for me. It reads all txt files with 'AVE' in the beginning. Then takes exact name of file and change directory to read the file.
 Files=dir('**/AVE*.txt');
for k=1:length(Files)
    for i=1:k
        FileNames=fullfile(Files(k).folder,Files(k).name);
        cd (Files(i).folder);
        ImpFiles(i,:)=dlmread(Files(i).name);
    end
end

3 个评论
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Jan 2018-7-12

It is not safe to change the current folder by cd. Note that any callback of GUIs or timers can change the current folder unexpectedly also. So better use the absolute path. See my answer.

The two loops are not useful. You create the variable "FileNames", but do not use it. So the loop over k is meaningless.

By the way: does this answer solve your problem? If not, accepting it is not useful, because the readers in the forum think, that your question is solved already.

Alexandr Lozak 2018-7-12

Thank you, Jan. Your answer and explanations better than mine. Could you give me hint. How can i load those files directly and in 10 different arrays. I have 10 folders with 5-3 txt files inside. How i can load them in similar way?

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