Python中二维数组按照某行或列排序的实现方法

import numpy as np

>>> a

array([[ 2, 7, 4, 2],

    [35, 9, 1, 5],

    [22, 12, 3, 2]])

>>> a[np.lexsort(a.T)]

array([[22, 12, 3, 2],

    [ 2, 7, 4, 2],

    [35, 9, 1, 5]])

>>>a[np.lexsort(-a.T)]

array([[35, 9, 1, 5],

    [ 2, 7, 4, 2],

    [22, 12, 3, 2]])

>>> a[np.lexsort(a[:,::-1].T)]

array([[ 2, 7, 4, 2],

    [22, 12, 3, 2],

    [35, 9, 1, 5]])

>>> a.T[np.lexsort(a)].T

array([[ 2, 4, 7, 2],

    [ 5, 1, 9, 35],

    [ 2, 3, 12, 22]])

>>> a.T[np.lexsort(a[::-1,:])].T

array([[ 2, 2, 4, 7],

    [ 5, 35, 1, 9],

    [ 2, 22, 3, 12]])