Reading data from csv files

I have 37 csv files. I need to read data from first row of all the 37 files and merge these 37 rows into one mat file.

Then I will read all the 2nd rows and merge them into one mat file.

I will keep reading the data till the last row of each csv file.

Name of my csv files are:

Col01_all
Col02_all
.
.
.
Col37_all

I am not sure how to do this.

[Adam Danz]

I suggest you read the entire files into matlab (in a loop) and then collate the rows as needed after the data are in your workspace.

[Stephen23]

Read the files in a loop, using sprintf to generate the filenames:

https://www.mathworks.com/help/matlab/import_export/process-a-sequence-of-files.html

As Adam Danz wrote, it would be easiest if you simply import the whole files and the use indexing to select the rows that you need.

[Ahmad Hasnain]

Thanks.

https://www.mathworks.com/help/matlab/import_export/process-a-sequence-of-files.html

This link was very helpful.

[dpb]

"Read the files in a loop, using sprintf to generate the filenames:"

For that type of a set of file names, I'd use the dir solution with a wildcard as being simpler...

d=dir(fullfile(wkdir,'Col*all.csv'));  % presuming there is a .csv extension
for i=1:numel(d)
   import/process file fullfile(wkdir,d(i).name)) here
end

[Ahmad Hasnain]

I have extracted the data from all csv files using the following code.

csvfiles = dir('*.csv') ; 
N = length(csvfiles) ; 
A = cell(N,1) ;
for i = 1:N
    A{i} = csvread(csvfiles(i).name);
end

Now I have a cell array that contains all the data. A{1,1}, A{2,1},...A{37,1}.

I want to extract the first row from A{1,1}, A{2,1},...{37,1} and then combine all the 37 rows in one mat file. How can I do that?

[KSSV]

Are you sure that all A{i} are of same size?

[Ahmad Hasnain]

Yes, they are all of the same size 15x38

Answer 1

[Guillaume]

%your original code, slightly modified
csvfiles = dir('*.csv'); 
filescontent = cell(numel(csvfiles), 1);
for i = 1:numel(csvfiles)
    filescontent{i} = csvread(csvfiles(i).name);
end

%write rows of matrices into mat file
destfolder = 'C:\somewhere\somefolder';
allcontent = cat(3, filescontent{:});  %concatenate all matrices into a 3D matrix
%save rows of each matrix into a mat file (as variable rows)
for rowidx = 1:size(allcontent, 1)
    rows = permute(allcontent(rowidx, :, :), [3 2 1]);  %extract rows.Permute so each matrix is a row of rows
    save(fullfile(destfolder, sprintf('row%d.mat', rowidx)), rows);
end