Why does json.dumps(list(np.arange(5))) fail while json.dumps(np.arange(5).tolist()) works

Question

I noticed this problem when a computer running Ubuntu was updated recently and the default version of Python changed to 2.7.

import json
import numpy as np

         


        

Answer 1

The problem is that with the first you don't get an int. You get a numpy.int64. That cannot be serialized.