Numpy: linked arrays?

Question

Python

>>> import numpy as np
>>> a = np.array([1,2,3])
>>> a
array([1, 2, 3])
>>> b=a
>>> b
array([1, 2, 3])
>>> b[0]=321
>>> a
array([321,   2,   3])

Why does a change when b changes? How to avoid it?

Answer 1

two variables point to one object.
You can avoid it like this