[New-bugs-announce] [issue22481] Lists within tuples mutability issue

[Владимир Тырин]

New submission from Владимир Тырин:

This behavior seems to be very strange. 

>>> l = [1, 2, 3]
>>> t = ('a', l)
>>> t
('a', [1, 2, 3])
>>> t[1] += [4]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'tuple' object does not support item assignment
>>> t
('a', [1, 2, 3, 4])

----------
messages: 227451
nosy: Владимир.Тырин
priority: normal
severity: normal
status: open
title: Lists within tuples mutability issue
type: behavior
versions: Python 2.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue22481>
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