access multiple csv files from different folder

Hi,

I have three folder in the drive namely 'D/Buck/V=12v' , 'D/Buck/V=24v' and 'D/Buck/V=48v'

each folder 4 differnt csv files namely 2k.csv,4k.csv,6k.csv and 8k.csv.

Each csv has 5 cloumns. delete first column and rename other coulmn as OV_12v_2k, OI_12v_2k,IV_12v_2k and II_12v_2k ........ II_48V_8k

how to read all files from the three folers in editor.

and group data from each csv file like all 1column data in one file and and name the rows like like ' 12v_2 12v_4 12v_6 12v_8 24v_2 ............. 48v_8'

Could any one please help me to resolve the issue?

Answer 1

[yanqi liu]

% three folder in the drive namely 'D/Buck/V=12v' ,  'D/Buck/V=24v' and 'D/Buck/V=48v'
% 4 differnt csv files namely 2.csv,4.csv,6.csv and 8.csv
% group data from each csv file like all 1column data in one file and and name the rows 
% like ' 12v_2 12v_4 12v_6 12v_8 24v_2 ............. 48v_8'
data = [];
for i = 1 : 1 : 3
    fd = fullfile(sprintf('D:/Buck/V=%dv', i*12))
    for j = 1 : 1 : 4
        fi = fullfile(fd, sprintf('%d.csv', j*2))
        % read data
        di = xlsread(fi);
        data{end+1,1} = sprintf('%dv_%d', i*12, j*2);
        data{end, 2} = di(:)';
    end
end
data
xlswrite('result.xlsx', data);

[Venkatkumar M]

Thanks for help @yanqi liu.

still have one issue.

The output is saving as cell array, instead could it saved as table or excel sheet. so it can be easy to read.

Even all column data are stored in row.

each array can has to be 4 columns.

or all can be store in one table

Could you please help with this?

[yanqi liu]

% three folder in the drive namely 'D/Buck/V=12v' ,  'D/Buck/V=24v' and 'D/Buck/V=48v'
% 4 differnt csv files namely 2.csv,4.csv,6.csv and 8.csv
% group data from each csv file like all 1column data in one file and and name the rows 
% like ' 12v_2 12v_4 12v_6 12v_8 24v_2 ............. 48v_8'
data = [];
for i = 1 : 1 : 3
    fd = fullfile(sprintf('D:/Buck/V=%dv', i*12))
    for j = 1 : 1 : 4
        fi = fullfile(fd, sprintf('%d.csv', j*2))
        % read data
        di = xlsread(fi);
        data{end+1,1} = sprintf('%dv_%d', i*12, j*2);
        data(end, 2:length(di)+1) = num2cell(di(:)');;
    end
end
data
xlswrite('result.xlsx', data);

[Venkatkumar M]

@yanqi liu

Unable to perform assignment because the size of the left side is 1-by-1048576 and the size of the right side is
1-by-5242880.

Error in Untitled7 (line 11)
          data(end, 2:length(di)+1) = num2cell(di(:)');;

error in code

could you please help with it?

[yanqi liu]

% three folder in the drive namely 'D/Buck/V=12v' ,  'D/Buck/V=24v' and 'D/Buck/V=48v'
% 4 differnt csv files namely 2.csv,4.csv,6.csv and 8.csv
% group data from each csv file like all 1column data in one file and and name the rows 
% like ' 12v_2 12v_4 12v_6 12v_8 24v_2 ............. 48v_8'
data = [];
for i = 1 : 1 : 3
    fd = fullfile(sprintf('D:/Buck/V=%dv', i*12))
    for j = 1 : 1 : 4
        fi = fullfile(fd, sprintf('%d.csv', j*2))
        % read data
        di = xlsread(fi);
        data{end+1,1} = sprintf('%dv_%d', i*12, j*2);
		tmp = num2cell(di(:)');
        data(end, 2:length(tmp)+1) = tmp;
    end
end
data
xlswrite('result.xlsx', data);

Answer 2

[Stephen23]

This should get you started. Because you did not upload any sample files I could not test it, therefore it will probably not work: you will need to modify it to suit your particular file formats and your required output file format. To do that you will need to read the documentation for the functions etc and make modifications to suit your data and needs. If you upload some sample files, then I can help you with that.

P = 'D/Buck';
C = {};
for ii = [12,24,48]
    D = sprintf('V=%dv',ii);
    for jj = [2,4,6,8]
        F = sprintf('%d.csv',jj);
        T = readtable(fullfile(P,D,F));
        T{:,'name'} = sprintf("%dV_%d",ii,jj); % these would be better as two numeric variables/columns.
        C{end+1} = T;
    end
end
Z = vertcat(C{:}); % asusmes all files have exactly the same format.
writetable(Z, 'myfile.csv')

[Venkatkumar M]

i am not sure why it is giving this error but it trying all files at a time

    Error using readtable (line 216)
Unable to open file 'D:\DC-DC\BUCK\Asynch\SiC\V=12\20k.csv40k.csv60k.csv80k.csv'.

Error in Untitled6 (line 9)
        T = readtable(fullfile(P,D,F));

[Stephen23]

"...it trying all files at a time"

You are right, I have fixed the code in my answer. It should be like this:

for jj = [2,4,6,8]
%          ^ ^ ^  this needs to be a row vector, not a column vector.

[Venkatkumar M]

error

>> C{k} = T;
Undefined function or variable 'k'.

is it supposed to beC{:} = T;?

[Stephen23]

C{end+1} = T;