MATLAB: How to access a vector of a 3D array

3d arrayaccess a vectorcell

I have a code :
%%%%%%%%%%%%%%%%%%%%%%%%
for i = 1 : 3
    for j = 1 : 5
        P{i,j} = rand(1,2);
    end
end
P{1,:}(2)
 % I want to use this to access a certain vector from this 3D matrix P
 % But matlab told me "Bad cell reference operation". Can anyone tell me 
 % the reason and how to do it? Thanks a lot!

Best Answer

Using a cell array is an inefficient representation. Better use a 3D array:
P = zeros(3, 5, 2);
for i = 1 : 3
  for j = 1 : 5
    P(i,j,:) = rand(1,2);
  end
end
Now the indexing is trivial:
P(1, :, 2)
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