How can I combine every Nth row of a matrix into a new matrix using a loop?
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I have a huge matrix A:
A=[X,Y]
and would like to create a new matrix B using every Nth row of A:
B=[A(1,:); A((1+N),:); A((1+2N),:); ...; A((1+(length(X)-N)),:)]
where length(X)>>1000.
How can I create this new matrix B using a loop?
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Accepted Answer
Thomas
on 5 Oct 2012
Edited: Thomas
on 5 Oct 2012
Is this what you want? You do not need to use loops
% initial data
a=[1:10;11:20]'
% select every 3rd row
out = a(1:3:end,:)
3 Comments
Ransika Pathirana
on 10 May 2020
If i need to go through a for loop how am i going to do it?
Thank you!
Walter Roberson
on 10 May 2020
r__r_ = ceil(size(A,1)/N);
B = zeros(r__r_, size(A,2), 'like', A);
for r__r__ = 1 : r__r_
B(r__r__,:) = A(1 - N + r__r__*N, :);
end
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