Convert dictionary with tuples as keys to JSON

Question

I want to convert a dictionary to a JSON object, but my key is a tuple, hence I am getting an issue when I do that:

import json

d = {(300, 341): 4, (342, 426): 5}
json.dumps(d)

Error:

TypeError: keys must be str, int, float, bool or None, not tuple

How can I solve this and access key elements if converted to JSON?

Is it okay for you to cast the tuples to strings, for example? — Eric Ávila, Oct 22 '21 at 13:55
I thought the keys can be in list using defaultdict, but anyway its upto the OP — Ghost Ops, Oct 22 '21 at 13:56
@EricÁvila no I want it as tuple itself since I access want to access each tuple element from key — shee, Oct 22 '21 at 13:56
@mkrieger1 I get this error with that solution AttributeError: 'dict' object has no attribute 'iteritems' — shee, Oct 22 '21 at 13:58
@mkrieger1 but the tuples get converted to strings there I dont want that — shee, Oct 22 '21 at 14:01
There's no other way. At least not without rearranging the structure of the data which we can't guess what would work for you. — mkrieger1, Oct 22 '21 at 14:01
@shee are you using Python 2? that seems pretty important info. I guess it could be worth tagging it in the question? — rv.kvetch, Oct 22 '21 at 14:06
@rv.kvetch No they are not, they were trying to copy code from another answer that was written for Python 2. — mkrieger1, Oct 22 '21 at 14:07

warownia1 · Answer 1 · 2021-10-22T14:15:29.297

As the error states, tuples cannot be keys of JSON objects and you need some kind of a workaround. Consider serializing the tuples to strings, but converting them back to tuples might be a bit tricky in such case.

d = {str((300, 341)): 4, str((342, 426)): 5}
json.dumps(d)

Other option is to change the way you store your data to something like this

d = [
  {'key1': 300, 'key2': 341, 'value': 4},
  {'key1': 342, 'key2': 426, 'value': 5}
]

obviously you may change "key1" and "key2" to something more meaningful.

edit: As you mentioned you are working with ranges. How about this solution?

def jsonify_data(d):
  jsonifable = {'%d:%d' % key: val for key, val in d.items()}
  json.dumps(jsonifable)

def dejsonify_data(jd):
  d = {}
  for key, val in jd.items():
    start, end = key.split(':')
    d[int(start), int(end)] = val
  return d

score -1 · Answer 2 · answered Oct 22 '21 at 13:57

-1

You cannot convert a tuple to JSON directly, you would have to do it like this instead:

dict = {
  300: 4, 
  341: 4,
  342: 5,
  426: 5
}
json.dumps(dict)

answered Oct 22 '21 at 13:57

Ramón de León

94
8

cannot do that since 300-341 is a range so i stored them in tuple to check range conditions – shee Oct 22 '21 at 13:59
The answer is stated incorrectly: **tuples can be converted to JSON without issue**. The answer should specifically state that it applies to the case when tuples (or even lists) are used as keys in dictionaries. – rv.kvetch Oct 22 '21 at 14:04
Note also, that you're overriding the builtin type `dict` here. What happens when you do something like `dict()` in a following line? – rv.kvetch Oct 22 '21 at 14:07

Convert dictionary with tuples as keys to JSON

2 Answers2