Are instances of user-defined classes mutable?
ZHAOWANCHENG
zhaowcheng at 163.com
Thu Aug 6 00:17:17 EDT 2020
the doc of dictionary said "if a tuple contains any mutable object either directly or indirectly, it cannot be used as a key."
i think a instance of user-defined class is mutable, but i found it can be placed into a tuple that as a key of a dict:
>>> class mycls(object):
... a = 1
...
>>> me = mycls()
>>> me.a = 2 # mutable?
>>> {(1, me): 'mycls'}
{(1, <__main__.mycls object at 0x0000022824DAD668>): 'mycls'}
>>>
So are instances of user-defined classes mutable or immutable?
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