Tuple slices

Steven Bethard steven.bethard at gmail.com
Mon Jan 24 20:59:07 CET 2005


Fredrik Lundh wrote:
> Steven Bethard wrote:
>>
>>My impression was that full tuple copies didn't actually copy, but that slicing a subset of a 
>>tuple might.  Not exactly sure how to test this, but:
>>
>>py> a = 1, 2, 3
>>py> a[:2] is a[:2]
>>False
> 
> yup.  and to figure out why things are done this way, consider this case:
> 
>     >>> a = give_me_a_huge_tuple()
>     >>> len(a)
>     (a rather large number)
>     >>> b = a[:2]
>     >>> del a
> 
> (IIRC, I proposed to add "substrings" when I implemented the Unicode string
> type, but that idea was rejected, for the very same "and how do you get rid of
> the original object" reason)

Ahh.  Yeah, that seems sensible.  I don't think I've ever written code 
like that, but if I did, I'd almost certainly want it to work as it does 
now...

Steve



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