Conditional data extraction from csv file

I wish to extract the data from the file 'ddata' into separate excel files containing only the variable columns of

v7,v8,v9 & v10 with respect to the varying values of v3,v4,v5 & v6. The values of v3 varies from 1 to 5, v4 varies from 1 to 2,

v5 varies from 1 to 3, and v6 varies from 1 to 8. For example, the condition when v3=1,v4=1,v5=1 & v6=1 will create the first

excel file. Please help.

[dpb]

Use grouping variables and a loop or possibly splitapply

[Josh]

I tried this code, however facing some errors. Please help.

T = readmatrix("ddata.csv");
v3 = T(:,3);v4 = T(:,4);v5 = T(:,5);v6 = T(:,6);
[G GID] = findgroups(v3,v4,v5,v6);
func = @(x1) x1;
Y = splitapply(func,T,G);

for i = 1:numel(Y)

writematrix(Y(1,i),'data_i.xlsx');

end

[dpb]

I was suggesting you probably don't need to actually separate the data into files but process it with the aid of grouping variables instead. Creating 46 additional data files is creating additional pain to deal with to keep them all straight.

Unless there's an absolute specific need for the files themselves outside just processing the results or presenting them.

If insist on going that route, then the suggestion was more like

v = readmatrix("ddata.csv");
[g GID1,GID2,GID3,GID4]=findgroups(v(:,3),v(:,4),v(:,5),v(:,6));
ug=unique(g);
for i = 1:numel(ug)
  filename=sprintf('Data' repmat('_%02d',1,4) '.xlsx',GID1(i),GID2(i),GID3(i),GID4(i));     % or some other horrible name convention to tell them apart
  writematrix(v(g==ug(i),7:end),filename);
end

NB: Aircode -- untested.

[Josh]

I will need 12 files out of this parent file. There are some issues in the code especially the first core line inside for loop.

It is not executing. Please have a look.

[dpb]

I said it was "air code" -- the format string isn't enclosed in brackets to pull it all together into one string...

>> i=1;sprintf(['Data' repmat('_%02d',1,4) '.xlsx'],id1(i),id2(i),id3(i),id4(i))
ans =
    'Data_01_01_01_01.xlsx'
>> 

The Q? still is, why do you actually have to have files instead of just processing the groups?