Python 3.8.1 (tags/v3.8.1:1b293b6, Dec 18 2019, 23:11:46) [MSC v.1916 64 bit (AM
D64)] on win32
>>> import numpy as np
>>> a=np.array([0,1,2])
>>> a
array([0, 1, 2])
>>> b=a[0]
>>> b
0
>>> a[0]=a[1]
>>> a
array([1, 1, 2])
>>> a[1]=b
>>> a
array([1, 0, 2])
>>> 

Python 3.8.1 (tags/v3.8.1:1b293b6, Dec 18 2019, 23:11:46) [MSC v.1916 64 bit (AM
D64)] on win32
>>> import numpy as np
>>> a=np.array([0,1,2])
>>> a
array([0, 1, 2])
>>> a[[0,1]]=a[[1,0]]
>>> a
array([1, 0, 2])
>>> a.T[[0,1]]=a.T[[1,0]]
>>> a
array([0, 1, 2])
>>>

Python 3.8.1 (tags/v3.8.1:1b293b6, Dec 18 2019, 23:11:46) [MSC v.1916 64 bit (AM
D64)] on win32
>>> import numpy as np
>>> a=np.array([0,1,2])
>>> a
array([0, 1, 2])
>>> a[0], a[1] = a[1], a[0]
>>> a
array([1, 0, 2])
>>> a[0], a[1] = a[1], a[0].copy()
array([0, 1, 2])
>>>

Python 3.8.1 (tags/v3.8.1:1b293b6, Dec 18 2019, 23:11:46) [MSC v.1916 64 bit (AM
D64)] on win32
>>> import numpy as np
>>> a=np.array([0,1,2])
>>> a
array([0, 1, 2])
>>> np.concatenate(([1,0], [2]))
array([1, 0, 2])
>>>