On Wed, 01 Jul 2009 20:39:06 +1200, Lawrence D'Oliveiro wrote:
> In message <mailman.2140.1245996088.8015.python-l...@python.org>, João
> Valverde wrote:
>
>> Simple example usage case: Insert string into data structure in sorted
>> order if it doesn't exist, else retrieve it.
>
> the_set = set( ... )
>
> if str in the_set :
> ... "retrieval" case ...
Not terribly useful, because there's no way of attaching any data to
retrieve to the key. Apart from the case of interning strings (or other
keys), you'd probably want a dict rather than a set:
if str in the_dict:
return the_dict[str]
else:
the_dict[str] = something_or_other
> else :
> the_set.add(str)
> #end if
> Want sorted order?
>
> sorted(tuple(the_set))
>
> What could be simpler?
Dropping the entirely superfluous creation of a tuple:
sorted(the_set)
That's a reasonable approach for small sets of data, but it isn't very
useful if the_set contains 4GB of keys, because you have to duplicate the
keys, then sort them. More effective would be a data structure that was
always sorted. This has the further advantage that it's even simpler than
sorted(the_set):
the_set
--
Steven
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