For loop with horzcat

Why does this not success?? Would someone help me correct the code?

A=[1 5; 3 3; 8 6; 4 8; 9 14; 11 11; 13 12; 15 7; 17 15; 1 20]
B=[]
for i=1:5
 for j=1:5
 B(i,:)=horzcat(B(i,:),A(i+j-1,:));
 end
end

I'd like to get this

B=[1 5 3 3 8 6 4 8 9 14;3 3 8 6 4 8 9 14 11 11; 8 6 4 8 9 14 11 11 13 12; 4 8 9 14 11 11 13 12 15 7;9 14 11 11 13 12 15 7 17 15;11 11 13 12 15 7 17 15 1 20]

Answer 1

[Matt J]

Another way,

AA=reshape(A.',[],1).';
B=cell(numel(AA),1);
for i=1:2:11
    
    B{i}=AA(i:i+9);
    
end

B=cell2mat(B)

[Ryosuke Saito]

Thanks so much! This is exactly what I'd like to do and I found this works!!

Answer 2

[Matt J]

horzcating in for-loops is bad practice. Better to do,

AA=reshape(A.',[],1).';

B=AA(  (1:10)+(0:2:10).' )

[Ryosuke Saito]

Thanks for your comment. I am sorry that I set up a simple table as the contents of A here. Actual contents of A in the computation I am trying to do is much complicated. So the proposed solution is not useful.

[Matt J]

My solution is independent of the contents of A.