Take lines from array
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I have an 64X4 array A , and I want take out every first 2 lines in every 4 line, is there some easy way to do that?
Accepted Answer
A = repmat([1 1 1 1; 2 2 2 2; 3 3 3 3; 4 4 4 4],16,1); % Example matrix
B = zeros(32,4); % Preallocate B
B(1:2:end) = A(1:4:end,:); % Take line 1 of every 4.th line in A
B(2:2:end) = A(2:4:end,:); % Take line 2 of every 4.th line in A
results in:
A =
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
B =
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
1 1 1 1
2 2 2 2
More Answers (1)
KSSV
on 4 Jan 2019
A = rand(64,2) ;
B = reshape(A',2,4,[]) ;
B = permute(B,[2 1 3]) ;
iwant = B(1:2,:,:) ;
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