You can use the fftshift and ifftshift functions to swap left and right halves of a vector.

Create a vector containing an odd number of elements, and swap the left and right sides of the vector using the fftshift function.

V = [1 2 3 4 5 6 7];
X = fftshift(V)

X = 1×7

     5     6     7     1     2     3     4

Use the ifftshift function to swap the left and right sides of X. The result is the same as the original vector V.

Y = ifftshift(X)

Y = 1×7

     1     2     3     4     5     6     7

Calling the fftshift function twice does not necessarily reconstruct the original input.

fftshift(fftshift(V))

ans = 1×7

     2     3     4     5     6     7     1

Rearrange the rows of a matrix to shift the nonnegative elements to the left.

Y = [-2 -1 0 1 2; 
    -10 -5 0 5 10];
X = ifftshift(Y,2)

X = 2×5

     0     1     2    -2    -1
     0     5    10   -10    -5