Cut differently odd and even rows in matrix

Hi, all!

I have a matrix like that:

a = [ 1     2     3     4     5     6     7     8;
      9    10    11    12    13    14    15    16;
     17    18    19    20    21    22    23    24;
     25    26    27    28    29    30    31    32];

I need to get this matrix:

 [ 3     4     5     6     7     8;
   9    10    11    12    13    14;
  19    20    21    22    23    24;
  25    26    27    28    29    30];

I want to cut first two values in odd lines and cut last two values in even lines. I means that I need something like this:

a = a(3:8, 1:2:end) && a(1:6, 2:2:end)

But it is incorrect. How can I do it correctly?

Answer 1

[Alexandra Harkai]

n = size(a, 2); % number of columns
a(1:2:n,:) = a(1:2:n,[[3:n],[1:2]]); % move first 2 elements in odd rows to the end
a = a(:, 1:n-2); % get rid of last 2 columns

Of course prettier to use circshift:

n = size(a, 2); % number of columns
a(1:2:n,:) = circshift(a(1:2:n,:),-2,2); % move first 2 elements in odd rows to the end
a = a(:, 1:n-2); % get rid of last 2 columns