Key (0, 0) is not a string when dumping json to a file- python

Question

I'm trying to dump a dictionary to a json file using the code below:

import json
with open('save.json', 'w') as outfile:
    json.dump({
        (0, 0): 0,
        (0, 1): 1,
        (1, 0): 0,
        (1, 1): 1,
    }, outfile)

But I'm having an issue with using tuples as keys. This works when I define a dictionary, but when I try to dump it to a file it gives this error:

TypeError: key (0, 0) is not a string

I'm using Python 3 on a linux based machine.

Any help fixing this would be appreciated.

There is no "fixing this" - JSON object keys are always strings, by definition. Change the tuples to strings, then the error goes away. — Amadan, Dec 25 '18 at 06:36

score 2 · Accepted Answer · answered Dec 25 '18 at 06:36

JSON standard requires keys being strings. If your purpose is saving this dictionary into a file - consider using pickle module:

import pickle
with open('save.json', 'w') as outfile:
    pickle.dump({
        (0, 0): 0,
        (0, 1): 1,
        (1, 0): 0,
        (1, 1): 1,
    }, outfile)

Key (0, 0) is not a string when dumping json to a file- python

1 Answers1