I wanted to combine 100 csv files for plotting in Matlab. All the files have same number of columns and rows. Can anyone help?

I Used the following code.But it is not working

csvFiles = dir('*.csv') ;

N = length(csvFiles) ;

for i = 1:N

T = readtable(csvFiles(i).name) ;

end

Answer 1

[Voss]

your_folder = 'folder where the csv files are'; % absolute or relative path
csvFiles = dir(fullfile(your_folder,'*.csv')) ;
names = fullfile({csvFiles.folder},{csvFiles.name});
N = length(csvFiles);
for i = 1:N
    csvFiles(i).data = readtable(names{i});
end
% this works only if the tables read from the files all 
% have the same set of column names in the same order:
T = vertcat(csvFiles.data);

[Md Sadiq]

your_folder = '"D:\Education\WICKING RESEARCH\IMAS Freeze-Thaw and Moisture Sensor Results (1)"'; % absolute or relative path

csvFiles = dir(fullfile(your_folder,'*.csv')) ;

names = fullfile({csvFiles.folder},{csvFiles.name});

N = length(csvFiles);

for i = 1:N

csvFiles(i).data = readtable(names{i});

end

% this works only if the tables read from the files all

% have the same set of column names in the same order:

T = vertcat(csvFiles.data);

I run this.It;s giving the foloowing errror

Unrecognized field name "data".

Error in untitled8 (line 10)

T = vertcat(csvFiles.data);

[Md Sadiq]

My data looks like this. All the files have same first rows.I want the first row only once at the start of the merged file.

[Voss]

Unrecognized field name "data". means that the loop executed zero times, which means that no csv files were found by dir.

Remove the double quotes from the folder name. Use this:

your_folder = 'D:\Education\WICKING RESEARCH\IMAS Freeze-Thaw and Moisture Sensor Results (1)'; % absolute or relative path

instead of this:

your_folder = '"D:\Education\WICKING RESEARCH\IMAS Freeze-Thaw and Moisture Sensor Results (1)"'; % absolute or relative path

[Md Sadiq]

Thank you,it worked.

[Voss]

You're welcome!

[Md Sadiq]

Hello,

The data in column 10-17 (for the attached picture) are temperature in celcius unit.How I can convert these data in Farenheit unit? In excel,it's easy.But my number of rows exceed excel limit.So,I need to convert them in Matlab for plotting the temperature in Farenheit unit.Can you help?

[Voss]

readtable the file into a table T, then

T{:,10:17} = T{:,10:17}*9/5+32;

then writetable T out to a file.

Answer 2

[Mathieu NOE]

maybe this ?

here I wanted to do a vertical concatenation - up to you to change that portion of the code

also , if processing the files must absolutely be done with correctly sorted files , please consider using this Fex submission :

Natural-Order Filename Sort - File Exchange - MATLAB Central (mathworks.com)

fileDir = pwd; % current directory (or specify which one is the working directory)
outfile = 'OUT.dat'; % output file name 

S = dir(fullfile(fileDir,'*.csv')); % get list of data files in directory
S = natsortfiles(S); % sort file names into natural order , see : 
           %(https://fr.mathworks.com/matlabcentral/fileexchange/47434-natural-order-filename-sort)

out_data = [];

for k = 1:length(S)
    filename = S(k).name; %
    out = readmatrix( fullfile(fileDir, filename)); % 
    [m,n] = size(out);
    if (m<1) | (n<1)
        disp([' Warning : File :' filename ' is empty !'])
    else
        out_data = [out_data; out]; % vertical concatenation
    end
end


% store out_data in excel file 
writematrix(out_data,fullfile(fileDir,outfile),"Delimiter","tab");