unintended changes occur when dealing with list of list

[ZhihanChen]

BPO	27459
Nosy	@stevendaprano, @eryksun
Files	Screenshot from 2016-07-05 16-44-14.png

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2016-07-06.00:14:53.371>
created_at = <Date 2016-07-06.00:07:52.409>
labels = ['type-bug', 'invalid']
title = 'unintended changes occur when dealing with list of list'
updated_at = <Date 2016-07-06.01:57:12.065>
user = 'https://bugs.python.org/ZhihanChen'

bugs.python.org fields:

activity = <Date 2016-07-06.01:57:12.065>
actor = 'Zhihan Chen'
assignee = 'none'
closed = True
closed_date = <Date 2016-07-06.00:14:53.371>
closer = 'eryksun'
components = ['Demos and Tools']
creation = <Date 2016-07-06.00:07:52.409>
creator = 'Zhihan Chen'
dependencies = []
files = ['43633']
hgrepos = []
issue_num = 27459
keywords = []
message_count = 4.0
messages = ['269858', '269860', '269861', '269866']
nosy_count = 3.0
nosy_names = ['steven.daprano', 'eryksun', 'Zhihan Chen']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue27459'
versions = ['Python 3.5']

[ZhihanChen]

When creating list of list with multiplication, changing one element of a list will result in changing all lists.

[eryksun]

This is by design. Please read the answer for the frequently asked question "How do I create a multidimensional list?":

https://docs.python.org/3/faq/programming.html#how-do-i-create-a-multidimensional-list

[stevendaprano]

Hi Zhihan Chen, I see this issue is closed, but for future reference please don't post screenshots to report issues unless they are really needed. For text output, just copy the text from your terminal and paste it into your bug report. Making a screen shot is more work for you, less useful for us, and makes it impossible for the blind and visually impaired to read it using a screen-reader.

[ZhihanChen]

Oh I am really sorry for my carelessness. Please accept my apology. and thank you Steven, I will pay special attention to that.