在 Python 中强制复制一个小 int

2022-01-20 00:00:00 python 复制 int

问题描述

作为一个玩具问题，我试图想出对象 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

如 这里.

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?

解决方案

是的，这是可能的，而且没有低级的黑客或作弊:

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

我在本地使用 Python 3.8.1 执行此操作，但您也可以在 repl.it 复制它 和 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)

对于小的负面影响:

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

相关文章