[Python-ideas] exclusively1, common, exclusively2 = set1 - set2, set1 & set2, set2 - set1

[David Mertz]

Maybe the generalization isn't worthwhile.  I was thinking that maybe a
more general version should keep order in types that have order to start
with, so I confess I'm not certain what the "correct" interface would be.

But even if it were only for sets, I like the idea of a plain function much
better than a method of a set, even if the only arguments it accepted were
sets.


On Sat, Jul 6, 2013 at 10:28 PM, Paddy3118 <paddy3118 at gmail.com> wrote:

>
>
> On Sunday, 7 July 2013 03:53:09 UTC+1, David Mertz wrote:
>>
>> <snip>
>>
>   from collections import segment  # tentative name, see various
>> suggestions in thread
>>   only1, only2, intersection = segment(iter1, iter2)
>>
>> In behavior, this should do the same thing as the below (just faster):
>>
>>   def segment(iter1, iter2):
>>       set1, set2 = map(set, (iter1, iter2))
>>       return set1 - set2, set2 - set1, set1 & set2
>>
>
> Hi David, I really am not sure about generalizing the interface to
> iterators and then immediately turning them into sets in the
> implementation. I think the functionality can be naturally explained as an
> operation on two sets and should be restricted to sets. The caller should
> have to map other types to sets explicitly.
>
> If it turns out that the implemented algorithm in C would work just as
> well with one of the arguments being any finite iterator and the other
> needing to be a set then we could still stick with requiring two sets or
> change to a format of:
>
> set_only, common, iter_only = some_set.????(some_iterator)
>
>
>


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