just for fun
 

I'm re-creating the classic PacMan for the fun of it and needed a way to translate back and forth between directions and dx, dy for a sprite. Here was a fun solution that avoided cumbersome if...elif...elif...elif... chains. Any thoughts on readability, efficiency? Specifically, if this gets called by 4 monsters and 1 pacman every clock-tick = 1/60 sec, am I likely to run into trouble?

Jeff

def get_direction(dx,dy):



    dirs = {'dx == 0 and dy < 0': 'up',  # in actual program, maps to self.UP == 0

            'dx < 0 and dy == 0': 'left',

            'dx == 0 and dy > 0': 'down',

            'dx > 0 and dy == 0': 'right'}



    for d in dirs:

        if eval(d):

            return dirs[d]

    return None

Re: just for fun
 

Hi!

Well, at least it's an interesting way to do it :)

Because Python is an OO language, I would probably have a class Monster and an instance-variable self.current_direction. I think this would be cleaner.

Regards, mawe

Re: just for fun
 

I think you're right. The problem I was having was a disconnect between the direction and the dx, dy. The better solution is, IMO,

def get_direction(self):

   return self._direction



def set_direction(self, value):

  self._direction = value

  dx,dy = {UP:  (0,-1),

           LEFT: (-1,0),

           DOWN: (0,1),

           RIGHT:(1,0)} [self._direction]



direction = property(get_direction, set_direction)

Jeff