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list(ndarray) != ndarray.tolist()

See original GitHub issue

I stumbled over this:

import numpy as np
import json

ndarray = np.array([1, 2, 3], dtype=np.float32)

# works:
json.dumps(ndarray.tolist())

# does not work: json.dumps(list(ndarray))

Issue Analytics

State:
Created 6 years ago
Comments:7 (4 by maintainers)

Top GitHub Comments

1reaction

MartinThomacommented, Jan 30, 2018

Ah, I thought that there might be a special method similar to __iter__(). I guess changing __iter__() is not an option and probably this is what is used by list()?

1reaction

rlabbecommented, Jan 30, 2018

list() is part of Python. It cannot be rewritten to know about every type in existence. I go write the “RogerPy” module, introduce my own types, and list is supposed to know about it? Not possible.

list just iterates over an iterable: ‘return [i for i in x]’

It doesn’t know anything about the underlying type in x, it merely requires that it be iterable.

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