在Python中排序索引

Question

我有一个数组i1。我想按增加j顺序排列索引。例如，在[0，1]，i = 0，j = 1中。但是我有一个错误。预期的输出已附加。

import numpy as np

I1=np.array([[[0, 1],
        [0, 3],
        [1, 2],
        [1, 4],
        [2, 5],
        [3, 4],
        [3, 6],
        [4, 7],
        [5, 4],
        [6, 7]],

        [[0, 1],
        [0, 3],
        [1, 2],
        [1, 4],
        [2, 5],
        [3, 4],
        [3, 6],
        [4, 7]]])  

order1 = I1[0,:, 1].argsort()
I10 =np.array([I1[0][order1]])
print("I10 =",[I10])

错误是

in <module>
order1 = I1[0,:, 1].argsort()

IndexError: too many indices for array: array is 1-dimensional, but 3 were indexed

预期的输出是：

array([[[0, 1],
        [1, 2],
        [0, 3],
        [1, 4],
        [3, 4],
        [5, 4],
        [2, 5],
        [3, 6],
        [4, 7],
        [6, 7]],
       
        [[0, 1],
        [1, 2],
        [0, 3],
        [1, 4],
        [3, 4],
        [2, 5],
        [3, 6],
        [4, 7]]])

Answer 1

您需要使用键 sorted（） python内置功能：

import numpy as np

I1=np.array([[[0, 1],
        [0, 3],
        [1, 2],
        [1, 4],
        [2, 5],
        [3, 4],
        [3, 6],
        [4, 7],
        [5, 4],
        [6, 7]],
                [[0, 1],
                  [0, 3],
                  [1, 2],
                  [1, 4],
                  [2, 5],
                  [3, 4],
                  [3, 6],
                  [4, 7]]])  
I1 = np.array([sorted(i, key = lambda x : x[1]) for i in I1])
print(I1)

输出：

[list([[0, 1], [1, 2], [0, 3], [1, 4], [3, 4], [5, 4], [2, 5], [3, 6], [4, 7], [6, 7]])
 list([[0, 1], [1, 2], [0, 3], [1, 4], [3, 4], [2, 5], [3, 6], [4, 7]])]