[issue38245] Why am I getting inconsistent results in this simple List assignment?

[Ammar Askar]

Ammar Askar <ammar at ammaraskar.com> added the comment:

Check out this part of the FAQ: https://docs.python.org/3/faq/programming.html#how-do-i-create-a-multidimensional-list

Essentially, when you did `C = 2*[[]]`, what happens is that the SAME empty list is placed into C[0] and C[1]. Whereas when you do `M = [[],[]]`, you're creating two different lists. You can confirm this using:

>>> C = 2*[[]]
>>> C[0] is C[1]
True
>>> M = [[],[]]
>>> M[0] is M[1]
False

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nosy: +ammar2
resolution:  -> not a bug
stage:  -> resolved
status: open -> closed

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue38245>
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