order independent hash?

[88888 Dihedral]

On Monday, December 5, 2011 7:24:49 AM UTC+8, Ian wrote:
> On Sun, Dec 4, 2011 at 4:17 PM, 88888 Dihedral
> <dihedr... at googlemail.com> wrote:
> >> Please explain what you think a hash function is, then.  Per
> >> Wikipedia, "A hash function is any algorithm or subroutine that maps
> >> large data sets to smaller data sets, called keys."
> >>
> >> > Are you miss-leading the power of true OOP ?
> >>
> >> I have no idea what you are suggesting.  I was not talking about OOP at all.
> >
> > In python the (k,v) pair in a dictionary k and v can be  both an objects.
> > v can be a tuple or a list.  There are some restrictions on k to be an
> >  hashable type in python's implementation. The key is used to compute the position of the pair to be stored in a  hash table. The hash function maps key k to the position in the hash table. If k1!=k2 are both  mapped to the same
> > position, then something has to be done to resolve this.
> 
> I understand how dicts / hash tables work.  I don't need you to
> explain that to me.  What you haven't explained is why you stated that
> a hash function that operates on objects is not a hash function, or
> what you meant by "misleading the power of true OOP".

Do you  forget the memory management of a dictionary in Python that has 
to be linked for a dynamical growing and shrinking number of (k,v) pairs 
in a long period of time?

Avoiding the true non-trivial part in any implementation or use of a dictionary  is miss leading ? 

Probing too deep in the stack or occupying too much in the heap is not
bug free?