New submission from 2106 Hyunwoo Oh :
If you do the following:
lists=[[]]*100
lists[1].append('text')
print(lists[2])
you can see lists[2] contains 'text' even though it was appended to lists[1] in
the text. A little more investigation with the id() function can show that the
lists are shallowly copied when list multiplication occurs. I think this can
confuse users when they try to use list multiplication to create nested lists,
as they expected a deep copy to occur.
--
components: Demos and Tools
messages: 401625
nosy: ohwphil
priority: normal
severity: normal
status: open
title: Shallow copy occurs when list multiplication is used to create nested
lists; can confuse users
type: behavior
versions: Python 3.9
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<https://bugs.python.org/issue45169>
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