Date: Dec 28, 2012 12:56 PM
Author: uny gg
Subject: extract the rows except the specific index

Hello, I am newbie.. for matlab.. 

I would like to extract the rows except the specific index..

For example,

A = (1,2,3;4,5,6;7,8,9;10,11,12;13,14,15;16,17,18) % 6 by 3 matrix.

What I want to do is..
divide this matrix, 3 by 3 and 3 by 3 matrix randomly ...
Here is what I try.

bottom =1;
top =6;

ran_idx = bottom + (top - bottom)*rand([1,3]);
ran_idx = ceil(ran_idx);

train = A(ran_idx,:);
test = A(~ran_idx.:); % this one is not working,, return. empty matrix..

I can extract the train matrix.. but I could not make test..

Could you please somebody answer thie one?