[Python-Dev] Retrieve an arbitrary element from a set without removing it

[Alex Martelli]

Next(s) would seem good...

Alex

Sent from my iPhone

On Oct 24, 2009, at 6:47 PM, John Arbash Meinel <john.meinel at canonical.com 
 > wrote:

> Adam Olsen wrote:
>> On Fri, Oct 23, 2009 at 11:04, Vitor Bosshard <algorias at gmail.com>  
>> wrote:
>>> I see this as being useful for frozensets as well, where you can't  
>>> get
>>> an arbitrary element easily due to the obvious lack of .pop(). I ran
>>> into this recently, when I had a frozenset that I knew had 1 element
>>> (it was the difference between 2 other sets), but couldn't get to  
>>> that
>>> element easily (get the pun?)
>>
>> item, = set_of_one
>>
>>
>
> Interesting. It depends a bit on the speed of tuple unpacking, but
> presumably that is quite fast. On my system it is pretty darn good:
>
> 0.101us "for x in s: break"
> 0.112us "x, = s"
> 0.122us "for x in s: pass"
>
> So not quite as good as the for loop, but quite close.
>
> John
> =:->
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