4-d arrays not filling the loop output properly

I am trying to create a 4-d matrix by extracting data from a 3-d array within a loop. But the results are not as expected. I expect to fill the aod_nonan(:, :, :, 1) with aod_final_arng(:, :, 1:160) and aod_nonan(:, :, :, 2) with aod_final_arng(:, :, 161:320) but both are filled with the second set of results only. I am sure there is a problem here which I can't figure out. Could anyone help please? I have attached sample data.

load aod_final_arng; 
for i = 1:2;
    for k = 1:160:320;
aod_nonan(:, :, :, i) = aod_final_arng(:, :, k:(k-1)+160);
    end;
end;

Answer 1

[Walter Roberson]

You do not need the loop.

asz = size(aod_final_arng);
aod_nonan = reshape(aod_final_arng, asz(1), asz(2), 160, []);

[Sagar Parajuli]

Thank you very much, reshape should work for me. But I want to understand what is the problem in the above loop. Could you please explain why the loop is not storing the data as I would expect?

[Walter Roberson]

for i = 1:2;
    for k = 1:160:320;
aod_nonan(:, :, :, i) = aod_final_arng(:, :, k:(k-1)+160);

left hand side is indexed by i but not by anything involving k . So each iteration of k it is going to store into the same location on the left.

What you should have done was something like

kvals = 1:160:320;
for i = 1 : length(kvals)
   k = kvals(i);
   aod_nonan(:, :, :, i) = aod_final_arng(:, :, k:k+160-1);
end

[Sagar Parajuli]

Thank you, this is perfect, exactly what I was looking for, k_vals should be kvals though. Thank you for explaining.

[Walter Roberson]

You are right, I mis-typed.