making a copy of an array in python [duplicate]

Question

I am trying to make a copy of a numpy array in python. I would then like to change some values of the new array, however somehow this also changes the original?

Why is the following code not correct?

import numpy as np

a = np.array([1,1])
print("Array a:",a)

b = a
b[0] = a[0]*2
print("Array b after manipulation:", b)

print("Array a, after manipulating array b", a)

The only way I can make it work is by list comprehensions.

import numpy as np

a = np.array([1,1])
print("Array a:",a)

b = [x for x in a]
b[0] = a[0]*2
print("Array b after manipulation:", b)

print("Array a, after manipulating array b", a)

Answer 1

Assignment statements in Python do not copy objects, you need to use copy():

b = a.copy()