在Numpy中通过逻辑索引获取矩阵的网格

问题描述

我正在尝试使用numpy重写函数，该函数最初在MATLAB中.在MATLAB中有一个逻辑索引部分，如下所示:

I'm trying to rewrite a function using numpy which is originally in MATLAB. There's a logical indexing part which is as follows in MATLAB:

X = reshape(1:16, 4, 4).';
idx = [true, false, false, true];
X(idx, idx)

ans =

     1     4
    13    16

当我尝试使用numpy制作索引时，我无法获得正确的索引编制:

When I try to make it in numpy, I can't get the correct indexing:

X = np.arange(1, 17).reshape(4, 4)
idx = [True, False, False, True] 
X[idx, idx]
# Output: array([6, 1, 1, 6])

通过逻辑索引从矩阵中获取网格的正确方法是什么?

What's the proper way of getting a grid from the matrix via logical indexing?

推荐答案

您还可以这样写:

>>> X[np.ix_(idx,idx)]
array([[ 1,  4],
       [13, 16]])

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