List of point coordinates

[wimal]

How can I arrange list of point coordinates(x y ) ascending to X or Y  

[Lee Mac]

Ascending x-coordinate:

(vl-sort <point-list> '(lambda ( a b ) (< (car a) (car b))))

Ascending y-coordinate:

(vl-sort <point-list> '(lambda ( a b ) (< (cadr a) (cadr b))))

Ascending x-coordinate, then y-coordinate:

(vl-sort <point-list> '(lambda ( a b ) (if (equal (car a) (car b) 1e-8) (< (cadr a) (cadr b)) (< (car a) (car b)))))