Opening all .txt files in a folder and importing/saving columns of data separately which may be called upon and graphed.

Attached you will find code of the things that I have tried. I am having issues with the importing of the data. When I read from a single individual .txt file my code works but I am having issues implementing a way to do this with all .txt files in a folder. I have run impedance spectrums for neural cuffs and need to find a way to graph each working electrode in each cuff, in each medium, with three trials. Any help would be so appreciated.

Answer 1

[KSSV]

files = dir('*.txt') ;   % you are in the folder of files 
N = length(files) ;
% loop for each file 
for i = 1:N
    thisfile = files(i).name ;
    % do what you want 
end

[Sarah Brianne]

I am getting the error "Cell contents reference from a non-cell array object." Could you please help?

Fixed that with the curly brackets, this is currently a work in progress. Please let me know if you see any issues

Error in testFile (line 56)
   impDAT{i} = importdata(files{i}, delimiterIn, headerlinesIn);

delimiterIn = ' ';   
headerlinesIn = 8;
files=dir('C:\Users\Sarah\Desktop\Sarah_2018\DI_Trial_1');
files = dir('*.txt') ;   % you are in the folder of files 
N = length(files) ;
% loop for each file 
for i = 1:N
    thisfile = files(i).name ;
    impDAT{i} = importdata(files{i}, delimiterIn, headerlinesIn);
    DAT1{i}= abs(impDAT.data(:,3));
    DAT2{i}= impDAT.data(:,2);
    DAT3{i}= (impDAT.data(:,1));
    DAT4{i}= (impDAT.data(:,4));
    figure(1);
    subplot(2, 2, 1);
    plot(DAT2(i), DAT1(i), '.', 'Color', 'red');
    titstr=sprintf('Nyquist Plot');
    title(titstr,'FontSize',13);
    xlabel("Z'/ohm");
    ylabel('-Z"/ohm');
    grid on
    subplot(2, 2, 2);
    loglog(DAT3(i), DAT4(i), '.', 'Color', 'blue');
    titstr=sprintf('Frequency Vs. Impedance Plot');
    title(titstr,'FontSize',13);
    xlabel('Freq/Hz');
    ylabel('Z/ohm');
    grid on
end

[Stephen23]

@Sarah Soaf: today I formatted your code for you. In future please do it yourself:

• select the code text.
• press the {} Code button.
• ensure that there is an empty trailing line.

[Stephen23]

@Sarah Soaf: what is the purpose of these two lines?:

files=dir('C:\Users\Sarah\Desktop\Sarah_2018\DI_Trial_1');
files = dir('*.txt') ;   % you are in the folder of files

You use dir on some folder, allocating the output to the variable files. Then you discard those results and replace them with dir searching only the current directory for some text files. Perhaps you meant to do something like this:

D = 'C:\Users\Sarah\Desktop\Sarah_2018\DI_Trial_1';
S = dir(fullfile(D,'*.txt'));

[Sarah Brianne]

I will look at this soon, and let you know if works. Sorry have been busy do not think I was ignoring. Thank you so much for help.

[Sarah Brianne]

Sorry I have been on vacation. So I edited as you said and now am getting a strange error. When I look on it online the MATLAB answers on it do not really have a definitive answer just a discussion on possible causes.

delimiterIn = ' ';
headerlinesIn = 8;
D = 'C:\Users\Sarah\Desktop\Sarah_2018\DI_Trial_1';
S = dir(fullfile(S,'*.txt'));
N = length(S) ;
% loop for each file 
for i = 1:N
    %thisfile = files(i).name ;
   impDAT(i) = importdata(S, delimiterIn, headerlinesIn);
DAT1(i)= abs(impDAT.data(:,3));
DAT2(i)= (impDAT.data(:,2));
DAT3(i)= (impDAT.data(:,1));
DAT4(i)= (impDAT.data(:,4));

figure(1);
subplot(2, 2, 1);
plot(DAT2(i), DAT1(i), '.', 'Color', 'red');
titstr=sprintf('Nyquist Plot');
title(titstr,'FontSize',13);
xlabel("Z'/ohm");
ylabel('-Z"/ohm');
grid on;
hold on

subplot(2, 2, 2);
loglog(DAT3(i), DAT4(i), '.', 'Color', 'blue');
titstr=sprintf('Frequency Vs. Impedance Plot');
title(titstr,'FontSize',13);
xlabel('Freq/Hz');
ylabel('Z/ohm');
grid on;
hold off

My N does not seem to update with length of S and when I open impDAT there is only one folder with three files with one containing all the data I need to graph for one of the text files. This is the error I am getting.

Error using matlab.internal.editor.eval.FileInfo
Java exception occurred:
java.io.IOException: java.lang.RuntimeException: Internal Exception in reading MLX file :
fl:filesystem:AccessDenied

at com.mathworks.services.mlx.MlxFileUtils.writeCode(MlxFileUtils.java:204)

Caused by: java.lang.RuntimeException: Internal Exception in reading MLX file :
fl:filesystem:AccessDenied

  at com.mathworks.services.mlx.MlxFileUtils.nativeWriteMlxFile(Native Method)

  at com.mathworks.services.mlx.MlxFileUtils.writeCode(MlxFileUtils.java:202)

Error in matlab.internal.editor.eval.TmpFilePath.get

Error in matlab.internal.editor.evaluateCode

Error in matlab.internal.editor.evaluateCode

Error using matlab.internal.editor.eval.FileInfo
Java exception occurred:
java.io.IOException: java.lang.RuntimeException: Internal Exception in reading MLX file :
fl:filesystem:AccessDenied

  at com.mathworks.services.mlx.MlxFileUtils.writeCode(MlxFileUtils.java:204)

Caused by: java.lang.RuntimeException: Internal Exception in reading MLX file :
fl:filesystem:AccessDenied

  at com.mathworks.services.mlx.MlxFileUtils.nativeWriteMlxFile(Native Method)

  at com.mathworks.services.mlx.MlxFileUtils.writeCode(MlxFileUtils.java:202)

Error in matlab.internal.editor.eval.TmpFilePath.get

Error in matlab.internal.editor.evaluateCode

Error in matlab.internal.editor.evaluateCode

Have you ever experienced this before?

Also I tried to format code for you but for some reason will not do it for the areas regarding plot. I apologize.

[Sarah Brianne]

I fixed that. Will dir work with 5 columns of data? My S is a 0x1 structure and I am trying to determine how to fix that.

[Stephen23]

"Will dir work with 5 columns of data?"

What does that mean? dir accepts an single character vector input, so it is not clear what you mean when you write that it "work with 5 columns of data": what columns? What data? What does "work with" actually mean in terms of MATLAB?

Your code has a bug, you need to use D, not S, like this:

D = 'C:\Users\Sarah\Desktop\Sarah_2018\DI_Trial_1';
S = dir(fullfile(D,'*.txt'));

[Sarah Brianne]

I saw that and already tried changing that and tried different folders

Answer 2

[Sarah Brianne]

So I have information from impedance spectrums. I have 5 columns of data Z,Z',Z'',Freq,Phase. I changed the error you said I have but when I try to use this code my S is a 0x1 with no data. The iterations of i is zero. My N is also equal to zero. There are text files in all the different folders I have tried opening.