在python中制作没有引用的列表列表 [英] Making a list of lists with no refrences in python

问题描述

我试图以单行有效的方式列出列表，但是我无法提出任何避免引用的方法.到目前为止，这是我尝试过的，显然没有成功:

I am trying to make a list of lists in a one-lined efficient manner, but I can't come up with any way to avoid having references. This is what I have tried so far, obviously unsuccessfully:

>>> test=[[None]*3][:]*3
>>> test
[[None, None, None], [None, None, None], [None, None, None]]
>>> test[0][0]=0
>>> test
[[0, None, None], [0, None, None], [0, None, None]]
>>> 

这不是我想要发生的事情.我想要的是让0成为仅第一个列表的第一项.我该怎么办?

This is not what I want to happen. What I want is for 0 to be the first item of only the first list. How can I do this?

推荐答案

使用列表理解:

test = [[None] * 3 for _ in range(3)]

(请注意，_只是与输出无关的约定，在本例中为0，1和2)

(Note the _ is just a convention for output that is irrelevant, in this case 0, 1, and 2)

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