MATLAB: How to shift a matrix

imwarpMATLABmatrixmatrix manipulation

Say I have a matrix that is 3×3:
1 2 3
4 5 6
7 8 9
I want to shift the top and bottom rows:
1 2 3
4 5 6
7 8 9
This would expand it into a 3×4 matrix yes but i mostly want to know how specifically to do this shifting. I was told the imwarp function could help but im not sure. I'm thinking I would have to define a matrix for the first one to shift to? Or something like that?

Best Answer

loop version:
M=[ 1,2,3;
    4,5,6;
    7,8,9; ];
C=nan(3,4);
for i=1:size(M,1)
    if mod(i,2)==1
        C(i,2:end)=M(i,:);
    else
        C(i,1:end-1)=M(i,:);
    end
end
vector slicing version:
M=[ 1,2,3;
    4,5,6;
    7,8,9; ];
L=mod([1:3]',2)>0;%logical 1 and 0 vector
A=M(L,:);
B=M(not(L),:);
C=nan(3,4);
C(L,2:4)=A;
C(not(L),1:3)=B;
M is input array
C is output array
empty elements is in 'NaN' type. you can get nan value index using 'isnan' function
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