Hashing in python

[MRAB]

Vish wrote:
> Hi,
> 
> I need to hash 3d coordinates to a grid which has been divided into
> 4*4*4 squares. Using python, I thought of a simple way as follows:
> 
> CELL_SIZE = 4
> 
> def key(point):
> 
>     return (
>         int((floor(point[0]/CELL_SIZE))*CELL_SIZE),
>         int((floor(point[1]/CELL_SIZE))*CELL_SIZE),
>         int((floor(point[2]/CELL_SIZE))*CELL_SIZE)
>     )
> 
> 
> Since python allows keys to be tuples, I think that this should work.
> Is there a better (more efficient) way to do it?
> 
floor(x) returns an integer, so floor(x/CELL_SIZE)*CELL_SIZE is an
integer multiple of CELL_SIZE, also an integer. There's actually no
point (unintentional pun!) to multiplying by CELL_SIZE:

CELL_SIZE = 4

def key(point):
     return (
         floor(point[0] / CELL_SIZE),
         floor(point[1] / CELL_SIZE),
         floor(point[2] / CELL_SIZE)
     )