why () is () and [] is [] work in other way?

Alexander Blinne news at blinne.net
Sat Apr 21 04:46:39 EDT 2012


Am 21.04.2012 05:25, schrieb Rotwang:
> On 21/04/2012 01:01, Roy Smith wrote:
>> In article<877gxajit0.fsf at dpt-info.u-strasbg.fr>,
>>   Alain Ketterlin<alain at dpt-info.u-strasbg.fr>  wrote:
>>
>>> Tuples are immutable, while lists are not.
>>
>> If you really want to have fun, consider this classic paradox:
>>
>>>>> [] is []
>> False
>>>>> id([]) == id([])
>> True
> 
> Huh. This is not what I would have expected. What gives?

This happens only because the first [] gets destroyed after evaluation
of id([]). The second [] then by accident gets the same id as the first
one had.

>>> a = []
>>> b = []
>>> id(a) == id(b)
False

Greetings



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