MATLAB: Loop through Matrix, to create multiple matrices from every nth row

Question

Hi.

I have a very large matrix (1600×19). Call this matrix A.

I want to create new matrices from this, t(i), and save them as new matrices.

I want the first new matrix to be contructed from rows 1, 17, 33, 49 etc… so for this, by my reckoning, I would write t1=A(1:16:end,:). Then the next matrix to consist of row 2, 18, 34, 50 etc.. And so on.

I would like to create a loop that would create 16 matrices this way.

I have started with

while i<17
t(i)=A(i:16:end,:)
end

I'm aware this is lacking something, just don't know what!! Any help is much appreciated, especially if there's some explanation of the logic. New to looping 🙂

Answer 1

What do you want to do with these matrices? Often, for this I would suggest crating a 16x19xp array where each slice in the third dimension is the sub arrays you want. Then you can work on those slices as necessary:

x = rand(1600,19);
x3d = permute(reshape(x.',19,[],16),[3 1 2]);

Will build the three d matrix. Now for the 17th "sub array"

x3d(:,:,17)