在Python中强制复制一个小int [英] Force copy of a small int in Python

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本文介绍了在Python中强制复制一个小int的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

作为一个玩具问题,我试图提出对象 a,b 这样

As a toy problem, I tried to come up with objects a, b such that

type(a) == type(b) == int # True
a + 1 == b + 1 == 1       # True
a is b                    # False

似乎 deepcopy 依赖于 _deepcopy_atomic ,如是否可以在Python中创建一个小int的副本?

Is it possible to create a copy of a small int in Python?

推荐答案

是的,这是可能的,并且没有低级的黑客或作弊行为:

Yes, it's possible, and without low level hacks or cheats:

>>> a = 0
>>> b = 9**99 % 9**99
>>> type(a) == type(b) == int
True
>>> a + 1 == b + 1 == 1
True
>>> a is b
False

我正在使用Python 3.8.1在本地进行此操作,但是您也可以在repl.it上复制它 www.python.org/shell/.

I'm doing this locally with Python 3.8.1, but you can also reproduce it at repl.it and at www.python.org/shell/.

对于小的积极因素:

>>> a = 7
>>> b = (9**99 + a) % 9**99
>>> b, type(b), a == b, a is b
(7, <class 'int'>, True, False)

对于小底片:

>>> a = -2
>>> b = (9**99 + a) % -9**99
>>> b, type(b), a == b, a is b
(-2, <class 'int'>, True, False)

这篇关于在Python中强制复制一个小int的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!

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