Processing cell arrays as a batch instead of one by one

i have 3 x 50 cells of cell array. i want to read those 50 cells row by row at a stretch and writing into a txt file. After executing the code below, the expeted result did not arrive. I inspected cluster_data variable, and i found that its size is 1x4 double instead of 50x4.It can be seen that Instead of reading all the 50 cells in a row, it just read only one cell. What to do?

iniclu = cell(1,1); %final size of iniclu is 3x50 with each cell containing 4 data
fid = fopen('iris_data2.txt', 'a');

for i = 1:3
    cluster_data = iniclu{i,:}; % I assuming 50 cells of 1st row is read into cluster_data when i = 1 and so on
    
    fprintf(fid, '%f,%f,%f,%f\n', cluster_data);
end
fclose(fid);
end

Pls clarify!

Answer 1

[Voss]

Perhaps this:

fprintf(fid, '%f,%f,%f,%f\n', iniclu{i,:});

Running example:

% example data (not sure whether this is similar to your data or not):
iniclu = {[1 2 3 4],[5 6 7 8];[9 10 11 12],[13 14 15 16]}

iniclu = 2×2 cell array
    {[   1 2 3 4]}    {[    5 6 7 8]}
    {[9 10 11 12]}    {[13 14 15 16]}

fid = fopen('iris_data2.txt', 'a'); % (I guess append mode is what you want)
for i = 1:size(iniclu,1)
    fprintf(fid, '%f,%f,%f,%f\n', iniclu{i,:});
end
fclose(fid);

% check the file's contents:
type('iris_data2.txt')

1.000000,2.000000,3.000000,4.000000
5.000000,6.000000,7.000000,8.000000
9.000000,10.000000,11.000000,12.000000
13.000000,14.000000,15.000000,16.000000

Answer 2

[Walter Roberson]

    cluster_data = iniclu{i,:}; % I assuming 50 cells of 1st row is read into cluster_data when i = 1 and so on
    

You are doing cell array expansion there. Your command is equivalent to

    [cluster_data, ~, ~, ~, ~, ~, ~, ~, ~, ~, .... ~] = iniclu{i,:}

You want something closer to

    cluster_data =  cell2mat(iniclu(i, :));