Immutable Array

20 Apr 2019

import numpy as np

a = np.array([1, 4, 5, 6])

print(a)

[1 4 5 6]

a[0] = 4

print(a)

[4 4 5 6]

a.flags.writeable = False

print(a)

[4 4 5 6]

a[2] = 3

---------------------------------------------------------------------------

ValueError                                Traceback (most recent call last)

<ipython-input-14-17351fe6de12> in <module>()
----> 1 a[2] = 3


ValueError: assignment destination is read-only

Rule:

You can’t change the value of a numpy array after it is marked with writeable False.

a.flags.writeable = True

a[2] = 8

print(a)

[4 4 8 6]

# flags.writeable = True will enable them to be updated