MATLAB: Filling in multidimensional array efficiently

arrayfor loopMATLAB

I need to fill in array of the size (900,1800,80,60) –> (tr,t,f,ch) through a for loop. In every iteration, I will get a bunch of data for a particular f and ch. This bunch, call it b, is the size of 50 by1800 and sometimes it is 49 by 1800.

Example:

array(?,:,f_1,ch_1) = b

I wish in each loop to fill in bunch b in my array. Is there an easy way to determine "?" in each loop? Alternatively, is there an easier way to fill in "array"?

Best Answer

If you want b to be inserted in the topmost rows of each array(:,:,f, ch), then it would be,

array(1:size(b,1),:,f, ch) = b

Related Solutions

MATLAB: Loop that creates arrays

If all the arrays are vectors (=1D arrays in matlab) you can store them in a matrix (=2D array).

% Pre-allocate an matrix with four "vector arrays"  of 6 elements each
A = zeros(4,6) ;

Here is an example to fill this array

for k=1:4
  A(k,:) =  (1:6) ./ k ; % just an example
end

To access a "array" (vector!) use indexing B = A(2,:) % get second row

If the vectors have different sizes, you need to look into cells and/or structs

A = {1:3 1:10 1:5} % a cell with 3 vectors
A{3} % third vector

MATLAB: Repeat 3-D array elements

Use the repmat function:

A = rand(67, 960, 80);
B = repmat(A, 1, 1, 3);
sizeB = size(B)

producing:

sizeB =
    67   960   240

Best Answer

Related Solutions

MATLAB: Loop that creates arrays

MATLAB: Repeat 3-D array elements

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