Re: Two aces up Python's sleeve

The wiked brain of ChatGPT gives me a lead:
PEP 659
Storing data caches before the bytecode.
Maybe its an effect of constant folding
and constant pooling by the compiler?
Mild Shock schrieb:

 For example this article:
 https://www.codementor.io/@arpitbhayani/python-caches-integers-16jih595jk
 about the integer singletons claims:
  >>> x, y = 257, 257
 >>> id(x) == id(y)
False
 But on Windows my recent CPython doesn't do that:
 Python 3.14.0a1 (tags/v3.14.0a1:8cdaca8, Oct 15 2024, 20:08:21)
 >>> x, y = 257, 257
 >>> id(x) == id(y)
True
 Mild Shock schrieb:

Hi,
>
In Java its possible to work this way
with the Integer datatype, just call
Integer.valueOf().
>
I am not sure whether CPython does the
same. Because it shows me the same behaviour
for small integers that are more than
>
only in the range -128 to 128. You can try yourself:
>
Python 3.14.0a1 (tags/v3.14.0a1:8cdaca8, Oct 15 2024, 20:08:21)
 >>> x,y = 10**10, 10**9*10
 >>> id(x) == id(y)
True
>
Maybe the idea that objects have an address
that can be accessed via id() has been abandoned.
This is already seen in PyPy. So maybe we
>
are falsly assuming that id() gives na object address.
>
Greg Ewing schrieb:

On 8/11/24 3:04 am, Mild Shock wrote:

This only works for small integers. I guess
this is because tagged pointers are used
nowadays ?

>
No, it's because integers in a certain small range are cached. Not sure what the actual range is nowadays, it used to be something like -5 to 256 I think.
>
BTW you have to be careful testing this, because the compiler sometimes does constant folding, so you need to be sure it's actually computing the numbers at run time.
>

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