How to pad numpy arrays on all sides with 0

Question

How to pad a 2D numpy array on all four sides with 0.

a = np.array([(1, 2, 3),(4, 5, 6)])

Answer 1

As mentioned, you can use numpy.pad.

You can use pad_width=1 and mode='constant'. You can add constant_values=0, but since 0 is the default value this is not necessary.

import numpy as np

a = np.array([(1, 2, 3),(4, 5, 6)])

res = np.pad(a, pad_width=1, mode='constant')

print(res)

# [[0 0 0 0 0]
#  [0 1 2 3 0]
#  [0 4 5 6 0]
#  [0 0 0 0 0]]