read files from 1 dic

Hi, i want to read various files from 1 past

but i have this error:

Instead its type was struct.

Error in interp (line 47)

validateattributes(idata,{'single','double'},{'vector'},'interp','x');

Error in Untitled_interpolar (line 33)

ecg_new = interp(ecg,5);

clear, close 
clc

path_dados_originais = "C:\Users\35191\OneDrive - Universidade de Aveiro\Emotional transition - recognition\Dados_Sessoes\S1.mat";
path_dados_interpolados = "C:\Users\35191\OneDrive - Universidade de Aveiro\Emotional transition - recognition\Dados_Sessoes\S1_interpolados";

cd(path_dados_originais)

Error using cd
Unable to change current folder to '/users/mss.system.uICeX0/C:\Users\35191\OneDrive - Universidade de Aveiro\Emotional transition - recognition\Dados_Sessoes\S1.mat' (Name is nonexistent or not a folder).

%Ficheiros a usar:
allfiles = dir;
Nfiles = size(allfiles(3:end,1),1);


% Transformação de .txt para .mat 

% for idx = 1:length(allfiles)
%     file_name = allfiles(idx).name;
% 
%     fprintf("Processing File %s\n",file_name);
%     data = importdata(file_name);
%     [filepath,name,ext] = fileparts(fullfile(pwd,file_name));
%    save([name '.mat'],'data');
% end

for j=1:Nfiles
    
    cd(path_dados_originais)
    %Ler os dados
    file = allfiles(j+2).name;

    eval(['load ' file ])
    ecg = data(:,1);

    ecg_new = interp(ecg,5);

    cd(path_dados_interpolados)
    mat_dados = [ecg_new]; 

    eval(['save' file(1:end-4) ' mat_dados'])
end

[Rik]

Why are you using this fragile code design with eval? Also, none of the code indicates what could be the source of the problem, so you will have to attach one of your mat files and explain what you want to happen.

Answer 1

[Samay Sagar]

The error message you're encountering indicates that the “interp” function expects its first argument to be a vector of type single or double, but it received a variable of type struct. If the data loaded from your MAT file is in the form of a struct, Passing the entire struct to “interp” instead of just a numeric vector would result in this error. It will be helpful if you can share the format of the input to the “interp” function.

Additionally, there's an error with the use of the “cd” command. You are attempting to change the directory to the path of a MAT file, which is not a directory. You should change the directory to the folder containing the MAT files, not the file itself.

Follow these steps to rectify your code:

• Ensure that the “path_dados_originais” is a directory, not a file .
• Use the correct field from the “struct” data loaded from the MAT file when calling “interp”.
• Change to the correct directory before starting the loop to process files.

Here's how you might change your code to fix those errors:

clear; close all; clc; 
% Define the directory paths 
path_dados_originais = "C:\Users\35191\OneDrive - Universidade de Aveiro\Emotional transition - recognition\Dados_Sessoes"; 
path_dados_interpolados = "C:\Users\35191\OneDrive - Universidade de Aveiro\Emotional transition - recognition\Dados_Sessoes\S1_interpolados"; 
% Ensure the output directory exists 
if ~exist(path_dados_interpolados, 'dir') 
    mkdir(path_dados_interpolados); 
end 
% Get a list of all MAT-files in the original data directory 
cd(path_dados_originais); 
allfiles = dir('*.mat'); % Only list .mat files 
Nfiles = length(allfiles); 
% Loop over each file to process 
for j = 1:Nfiles 
    % Load the data from the .mat file 
    file = allfiles(j).name; 
    data = load(file); 
    % Assume 'data' is a struct and 'ecg' is a field in it 
    % You may need to adjust this if the field name is different 
    if isfield(data, 'ecg') 
        ecg = data.ecg; 
    else 
        error('The loaded struct does not contain an ''ecg'' field.'); 
    end      
    % Validate that 'ecg' is a numeric vector before interpolation 
    validateattributes(ecg, {'single', 'double'}, {'vector'}, file, 'ecg');  
    % Interpolate the ECG data 
    ecg_new = interp(ecg, 5); 
    % Save the interpolated data to the new directory 
    save(fullfile(path_dados_interpolados, [file(1:end-4) '_interpolados.mat']), 'ecg_new'); 
end 

Read more about “interp” and “cd” here:

https://www.mathworks.com/help/signal/ref/interp.html

https://www.mathworks.com/help/matlab/ref/cd.html