在python中创建2d矩阵 [英] Creating a 2d matrix in python

问题描述

我创建了一个6x5的2d数组，最初每个单元格中只有一个.然后，我读取一个文件，并在读取它们时将其替换为数据.我首先创建一个空数组，因为数据在我正在读取的文件中处于未定义的顺序.我的第一次尝试是这样做的:

I create a 6x5 2d array, initially with just None in each cell. I then read a file and replace the Nones with data as I read them. I create the empty array first because the data is in an undefined order in the file I'm reading. My first attempt I did this:

x = [[None]*5]*6

这导致了一些我现在理解的奇怪错误，这是因为列表上的*运算符可能会创建引用而不是副本.

which resulted in some weird errors that I now understand is because the * operator on lists may create references instead of copies.

是否有一个简单的内衬即可创建此空数组?我可以做一些for循环并建立它，但这对于python来说似乎是不必要的冗长.

Is there an easy one liner to create this empty array? I could just do some for loops and build it up, but that seems needlessly verbose for python.

推荐答案

使用嵌套的理解列表:

x = [[None for _ in range(5)] for _ in range(6)]

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