Hi,
I have a v = 2x30 matrix and I need to take make another matrix to take all points of v whose y coordinates are positive
A:
I suggest that you read the documentation on matrix indexing, and specifically the part about logical indexing. I believe the solution you're looking for is something like this:
vSub = v(:,v(2,:) > 0); %# Extract columns where the second row is > 0
gnovice
2010-10-11 20:13:28
This is a solution for a 30x2 matrix, and for non-negative `y`, not strictly positive.
aschepler
2010-10-11 20:18:54
@aschepler: Right you are. Corrected now. I guess I'm too used to storing coordinate values in columns instead of rows.
gnovice
2010-10-11 20:22:19
A:
vPos = v(:, v(2,:) > 0);
creates the 2-by-n submatrix you described.
aschepler
2010-10-11 20:18:13