python 2d数组到字典 [英] python 2d array to dict

问题描述

我想从表示为二维数组的对称矩阵的下三角形创建一个字典.例如，如果 numpy 数组是;

I want to create a dict from lower triangle of a symmetric matrix represented as 2d array. For examples if the numpy array is;

array([[0, 2, 3],
       [2, 0, 4],
       [3, 4, 0]])

然后我希望字典看起来像；

then I want the dict to look like;

{('1', '0'): 2, ('2', '0'): 3, ('2', '1'): 4}

vector 也有类似的帖子；

There is a similar post for vector;

转换 Numpy 数组的最快方法成稀疏字典?

我对 python 比较陌生，所以感谢任何帮助/建议.

I am relatively new to python so any help/suggestoins appreciated.

推荐答案

>>> arr =[[0, 2, 3],
          [2, 0, 4],
          [3, 4, 0]]
>>> dict(((j,i), arr[i][j]) for i in range(len(arr)) for j in range(len(arr[0])) if i<j)
{(2, 0): 3, (1, 0): 2, (2, 1): 4}

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