Paolo Veronelli wrote:
> And mostly with sets remove operation expense should be sublinear or am
> I wrong?
> Is this fast as with lists?
It's faster then with lists... in sets, as with dicts, remove is on
average O(1).
> Obviously if I use the ids as hash value nothing is guaranted about the
> objects contents to be unique but I don't care.
> My work is a self organizing net,in which the nodes keep a structure to
> link other nodes.As the nature of the net,the links are moved frequently
> so remove and add operations and contains query should be optimized.
> Why objects need to be hashable for this? Isn't __hash__ there to solve
> the problem?
The idea of a set of mutable sets looks a bit odd to me...
I don't get why the outer container should be a set, since you don't
care about uniqueness... if you are representing a graph (which seems
the case to me), I'd use an identifier for each node, and a dictionary
mapping node-ids to its adjacency set for each node. For instance,
0 <-- 1 --> 2 --> 3
| |
v v
4 --> 5
would be represented as
{0: set([]), 1: set([0, 2]), 2: set([2,4]), 3: set([5]), 4: set([5]),
5: set([])}
If node ids are consecutive integers, you could also of course use a
list as the outer structure.
PS: we could also discuss this in italian in it.comp.lang.python :)
--
Ciao,
Matteo
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