Unexpected update result on the quickly nested list in Python [duplicate]

问题

This question already has answers here:

List of lists changes reflected across sublists unexpectedly (13 answers)

Closed 2 years ago.

Why couldn't the first element but the whole column be updated below?

>>> x=2*[2*[1]]
>>> x
[[1, 1], [1, 1]]
>>> x[0][0]=2
>>> x
[[2, 1], [2, 1]]

回答1:

Even tho this is a clear duplicate but use range:

>>> x=[[1 for i in range(2)] for x in range(2)]
>>> x
[[1, 1], [1, 1]]
>>> x[0][0]=2
>>> x
[[2, 1], [1, 1]]
>>> 

At least still able to do:

>>> x=[[1]*2 for x in range(2)]
>>> x[0][0]=2
>>> x
[[2, 1], [1, 1]]
>>> 

来源：https://stackoverflow.com/questions/52175690/unexpected-update-result-on-the-quickly-nested-list-in-python