按列排序，行变换

1.
import numpy as np
Z=np.random.randint(0,10,(5,5))
print("排序前：\n",Z)
print("Z[:,2]：\n",Z[:,2],type(Z[:,2]))
print("Z[:,2].argsort：\n",Z[:,2].argsort())
print("Z[:,2].argsort：\n",Z[Z[:,2].argsort()])
print(Z[np.array([3,4,1,2,0])])
print(Z[[3,4,1,2,0]])

排序前：
 [[7 3 1 5 3]
 [1 0 8 8 6]
 [8 7 1 3 6]
 [7 3 2 9 7]
 [5 3 5 5 0]]

Z[:,2]：
 [1 8 1 2 5] <class 'numpy.ndarray'>

Z[:,2].argsort：
 [0 2 3 4 1]

Z[:,2].argsort：
 [[7 3 1 5 3]
 [8 7 1 3 6]
 [7 3 2 9 7]
 [5 3 5 5 0]
 [1 0 8 8 6]]
----------------------->Z[列表或np数组]都是行变化

[[7 3 2 9 7]
 [5 3 5 5 0]
 [1 0 8 8 6]
 [8 7 1 3 6]
 [7 3 1 5 3]]
[[7 3 2 9 7]
 [5 3 5 5 0]
 [1 0 8 8 6]
 [8 7 1 3 6]
 [7 3 1 5 3]]


2.交换两行

A=np.arange(25).reshape(5,5)
print(A)
A[[0,1]]=A[[1,0]]
print(A)

[[ 0  1  2  3  4]
 [ 5  6  7  8  9]
 [10 11 12 13 14]
 [15 16 17 18 19]
 [20 21 22 23 24]]
[[ 5  6  7  8  9]
 [ 0  1  2  3  4]
 [10 11 12 13 14]
 [15 16 17 18 19]
 [20 21 22 23 24]]