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Created on 2012-10-18 19:59 by Julian, last changed 2022-04-11 14:57 by admin. This issue is now closed.
| Messages (4) | |||
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| msg173292 - (view) | Author: Julian Berman (Julian) * | Date: 2012-10-18 19:59 | |
I find the following to be unintuitive:
Python 3.3.0rc1 (default, Sep 6 2012, 16:02:32)
[GCC 4.2.1 Compatible Apple Clang 3.1 (tags/Apple/clang-318.0.58)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from collections import namedtuple
>>> F = namedtuple("F", "x")
>>> G = namedtuple("G", "y")
>>> F(12) == G(12)
True
I'm OK with not taking the class name into account, that sounds reasonable, but I think field names should make those unequal.
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| msg173316 - (view) | Author: Nick Coghlan (ncoghlan) *  |
Date: 2012-10-19 09:36 | |
So that they can be returned from an API without breaking backwards compatibility, named tuples are intentionally equivalent to the corresponding ordinary tuple:
>>> from collections import namedtuple
>>> Pair = namedtuple("Pair", "x y")
>>> Pair(1, 2) == (1, 2)
True
Transitivity thus requires that two named tuples with different field names also compare equal with each other:
>>> Pair2 = namedtuple("Pair2", "a b")
>>> Pair(1, 2) == (1, 2) == Pair2(1, 2)
True
>>> Pair(1, 2) == Pair2(1, 2)
True
So the field names on named tuples are just an access mechanism - they aren't part of the value of the instances.
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| msg173317 - (view) | Author: Nick Coghlan (ncoghlan) * |
Date: 2012-10-19 09:37 | |
"... returned from an API that previously returned an ordinary tuple ..." |
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| msg173575 - (view) | Author: Raymond Hettinger (rhettinger) * |
Date: 2012-10-23 01:42 | |
Nick, thanks for closing this one with a clear and accurate explanation. |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:57:37 | admin | set | github: 60483 |
| 2012-10-23 01:42:26 | rhettinger | set | messages: + msg173575 |
| 2012-10-19 09:37:20 | ncoghlan | set | messages: + msg173317 |
| 2012-10-19 09:36:41 | ncoghlan | set | status: open -> closed nosy: + ncoghlan messages: + msg173316 resolution: not a bug stage: resolved |
| 2012-10-18 19:59:43 | Julian | create | |