Is there any hashable built-in object is mutable in python?

Question

Curious about whether we can use hash() to check if an object is mutable or not?

See __hash__. Strictly speaking, it's possible. The requirement is that any properties involved in equality are immutable. Properties not involved in equality could be mutable. This is, however, extremely ill-advised. Why do you need to know if a particular object is mutable? — jpmc26
– jpmc26, Commented Aug 3, 2016 at 19:01
To what end? Why does it matter to you whether a given thing is mutable? That's not the problem you're trying to solve, that's how you're trying to solve it. — jonrsharpe
– jonrsharpe, Commented Aug 3, 2016 at 19:08
@jonrsharpe I think how to satisfy his curiosity is the problem he wants to solve. Is it reasonable? — Haochen Wu
– Haochen Wu, Commented Aug 3, 2016 at 19:17
@HaochenWu it's not unreasonable, but it's useful to mention, and more or less completely pointless to speculate on. — jonrsharpe
– jonrsharpe, Commented Aug 3, 2016 at 19:26

linw1995 · Accepted Answer · 2017-07-17 02:24:36Z

4

>>> from collections.abc import Hashable
>>> mutable = [list, bytearray, set, dict]
>>> immutable = [int, float, complex, str, tuple, frozenset, bytes]
>>> all(isinstance(x(), Hashable) for x in immutable)
True
>>> any(isinstance(x(), Hashable) for x in mutable)
False

all mutable objects are unhashable.

edited Jul 17, 2017 at 2:24

answered Mar 31, 2017 at 9:42

linw1995

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