Open multiple .csv files, process and save them in a structure

Hello guys,

im very new to Matlab and have to code my own program to analyse some data. I need to open multiple .csv files (done that with uigetfile), filter them for the needed data (which is in column 7 and starts at row 31, i have put in a photo of how my data looks). My problem is that i cant save the files the way i want after i have opened them. I need to filter and plot the extracted data afterwards. The code i have so far works but is only saving the first file.

My Plan was to save each data with the loop in a structure so that i can access them later. If there is another way to save the data, im fine with it too, doesnt have to be with a structure i just thought this could work.

[filename,pathname] = uigetfile('*.csv;','MultiSelect',"on");


for i = 1,length(filename)
    filen = filename(1,i);
    filepath=fullfile(pathname, filename);
    fid = fopen (filepath{i});
   

%[file,path]=uigetfile('*.csv');
A = textscan(fid, '%s%s%s%s%s%s%s%s%s%s%s%s%s','Delimiter',';'); 


%Umwandeln von Cell --> String
B=string([A{:}]);

%',' durch '.' ersetzen
B=replace(B,',', '.'); % ',' durch '.' ersetzen

% Aufteilen in Header und Messdaten
Daten.Header=B(1:30,:);
Daten.Messdaten=str2double(B(31:end,7));


end

I am using the Matlab AppDesigner.

Since this is my first question here i hope this is enough information.

Answer 1

[Stephen23]

You need to fix this line otherwise your loop will only iterate once:

for i = 1:length(filename)
%        ^ this must be a colon!

You also need to use indexing to allocate to the output array on each loop iteration, e.g.:

Daten(i).Header = ...
Daten(i).Messdaten = ...

Read more about structure arrays:

https://www.mathworks.com/help/matlab/matlab_prog/access-multiple-elements-of-a-nonscalar-struct-array.html

[JoKi]

Ahh thanks, so far it works now.

I have tried to name it Daten.Header(i) before, didnt know i had to put the (i) there.

Thanks alot!