json alters dict keys type

[kjm1102]

Why does json change my dictionary keys from integers to strings?

import json; dic={}
for i in range(2): dic[i]=[i, str(i)]
print(dic)
with open('dic', 'w') as f: json.dump(dic,f)
with open('dic', 'r') as f: print(json.load(f))

{0: [0, '0'], 1: [1, '1']}
{'1': [1, '1'], '0': [0, '0']}

>>> import sys; sys.implementation
[object_link_for_thonny=1061265408](name='micropython', version=(1, 20, 0), _machine='LILYGO TTGO LoRa32 with ESP32', _mpy=10502)

[ricksorensen]

CPython 3.8.10 give same result returning keys as strings with json.load(). json.dump("dic",f) writes file dic as;

$ cat dic
{"0": [0, "0"], "1": [1, "1"]}

See:
https://stackoverflow.com/questions/1450957/pythons-json-module-converts-int-dictionary-keys-to-strings

[kjm1102]

That stackoverflow was an interesting read. Coding languages remind me of junk yard dogs. No matter which one you're using they are always ready to bite you on the arse.

[peterhinch]

JSON is one of a number of serialisation solutions available in MicroPython. Each has its own benefits and drawbacks. See this doc for a review.