It’s a structured array. Use d2.item()
to retrieve the actual dict object first:
import numpy as np
d1={'key1':[5,10], 'key2':[50,100]}
np.save("d1.npy", d1)
d2=np.load("d1.npy")
print d1.get('key1')
print d2.item().get('key2')
result:
[5, 10]
[50, 100]