一键矢量转换如何工作?

当我在机器学习项目中工作时，我正在寻找一行代码来将我的标签变成一个热门的矢量.我在Reddit上遇到了来自u/benanne的漂亮代码行.

When I was working on my machine learning project, I was looking for a line of code to turn my labels into one-hot vectors. I came across this nifty line of code from u/benanne on Reddit.

np.eye(n_labels)[target_vector]

例如，对于target_vector = np.array([1, 4, 2, 1, 0, 1, 3, 2])，它返回一键编码的值:

For example, for a target_vector = np.array([1, 4, 2, 1, 0, 1, 3, 2]), it returns the one-hot coded values:

np.eye(5)[target_vector]
Out: 
array([[ 0.,  1.,  0.,  0.,  0.],
       [ 0.,  0.,  0.,  0.,  1.],
       [ 0.,  0.,  1.,  0.,  0.],
       ..., 
       [ 0.,  1.,  0.,  0.,  0.],
       [ 0.,  0.,  0.,  1.,  0.],
       [ 0.,  0.,  1.,  0.,  0.]])

虽然它确实可以工作，但是我不确定它如何或为什么起作用.

While it definitely does work, I'm not sure how or why it works.