切片numpy数组与所需行的列表 [英] Slice numpy array wth list of wanted rows

问题描述

我有一个numpy二维数组 A 和行号列表 row_set .我如何获得新的数组 B ，例如 row_set = [0，2，5] ，然后 B = [A_row [0]，A_row [2]，A_row [5]] ?

I have a numpy 2d array A, and a list of row numbers row_set. How can I get new array B such as if row_set = [0, 2, 5], then B = [A_row[0], A_row[2], A_row[5]]?

我想到了这样的东西:

def slice_matrix(A, row_set):
    slice = array([row for row in A if row_num in row_set])

但是我不知道如何获取row_num.

but I don't have any idea, how can I get a row_num.

推荐答案

使用 take():

In [87]: m = np.random.random((6, 2))

In [88]: m
Out[88]: 
array([[ 0.6641412 ,  0.31556053],
       [ 0.11480163,  0.00143887],
       [ 0.4677745 ,  0.43055324],
       [ 0.49749099,  0.15678506],
       [ 0.48024596,  0.65701218],
       [ 0.48952677,  0.97089177]])

In [89]: m.take([0, 2, 5], axis=0)
Out[89]: 
array([[ 0.6641412 ,  0.31556053],
       [ 0.4677745 ,  0.43055324],
       [ 0.48952677,  0.97089177]])

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