How to Insert desired rows from one matrix into a new one

This is a small example of the overall problem:

What I want to do is essentially filter out rows from the matrix with some desired property (in this case, that the sum of the row = 2), and then save it to a new matrix.

Any ideas? Thanks!

    v = [0 2 4 6 2; 
        2 0 0 0 0];
    count = 0;
    for i = 1:2
        k = v(i,:)
    if sum(k) == 2
        count = count + 1;
        P(count, :) = k;
    end
    end

Answer 1

[Walter Roberson]

P = v(sum(v,2) == 2, :);

Breaking this into steps:

t = sum(v,2);  %sum each row of the matrix. "2" means rows
rowmatches = (t == 2);   %true where the sum was 2
P = v(rowmatches, :);    %logical indexing to do the extraction

Answer 2

[Matt Fig]

v = [2 0 0;1 0 1;4 5 6;-1 1 2; 2 3 4] % Sample array.
P = v(sum(v,2)==2,:)