How to dynamically reshape matrix block-wise? [duplicate]

Answer 1

Use Matrix indexing!

B=[A(:,1:4);A(:,5:8)]

In a loop...

for ii=0:floor(size(A,2)/4)-1
   B([1+5*ii:5*(ii+1)],:)=A(:,[1+4*ii:4*(ii+1)] );
end