Separte Matrix depending on changing value in column

Hi!

I got the following problem. I got a (N,2) Matrix. Now I want to cut the Matrix in severval (n,2) matrices with N>=n, depending on a changing value in the second column. For example [a,1; b,2; c,2; d,1] sould be separated into 3 matrices [a,1] [b,2 c,2] [d,1].

Thanks!

Answer 1

[Voss]

Let X be your N-by-2 matrix. Then the following code will separate X into a cell array Y, each element of which is a slice of X according to the second column value:

idx = 1+[0; find(diff(X(:,2))); size(X,1)];
n = numel(idx)-1;
Y = cell(n,1);
for i = 1:n
    Y{i} = X(idx(i):idx(i+1)-1,:);
end