Author serhiy.storchaka
Recipients Ramchandra Apte, Sergey, aleax, ethan.furman, jcea, oscarbenjamin, serhiy.storchaka, terry.reedy
Date 2013-07-15.08:11:00
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Message-id <1373875860.44.0.153582623203.issue18305@psf.upfronthosting.co.za>
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> On the contrary, it will reduce memory usage and creation time compared to regular tuples, because in cases like:
>   c = a + b
> you do not have to spend time and memory for allocating and copying elements of "a".

This is not a common case. A common case is creating short tuples and keeping a lot of tuples in memory.

> The only case when it could use more memory is if you explicitly delete "c" after that operation. But this can be solved too, internal storage can be resized to a smaller value when its tail elements are not used any more.

No. For fast += you need keep not only a size of tuple, but also a size of of allocated memory. It's a cause of sys.getsizeof([1, 2]) > sys.getsizeof((1, 2)).

For fast + you need even more complicated internal structure.

Tuples should be compact and fast. You shouldn't optimize a rare case at the cost of regression in common usage.
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2013-07-15 08:11:00serhiy.storchakasetrecipients: + serhiy.storchaka, aleax, terry.reedy, jcea, ethan.furman, Ramchandra Apte, oscarbenjamin, Sergey
2013-07-15 08:11:00serhiy.storchakasetmessageid: <1373875860.44.0.153582623203.issue18305@psf.upfronthosting.co.za>
2013-07-15 08:11:00serhiy.storchakalinkissue18305 messages
2013-07-15 08:11:00serhiy.storchakacreate