Counting duplicate JSON keys in python

Question

I have a JSON file with multiple duplicate keys in the following format:

"data": {
    "nameA": {
        "result": someInt,
        "timestamp": "someTime"
    },
    "nameB": {
        "result": someInt,
        "timestamp": "someTime"
    },
    "nameA": {
        "result": someInt,
        "timestamp": "someTime"
    },
    "nameC": {
        "result": someInt,
        "timestamp": "someTime"
    }
}

I need to dynamically determine the number of instances of each key and print them out. What would be the best way to accomplish this for a JSON in this format?

Rather than be concerned with the "best" way, have you found any way to make this work? What are you unhappy about with your current approach? — roganjosh
– roganjosh, Commented Aug 16, 2018 at 13:51
Not exactly a duplicate, but this question might help you out: stackoverflow.com/questions/29321677/… — Simon Brahan
– Simon Brahan, Commented Aug 16, 2018 at 13:57
@roganjosh I haven't found an approach that works yet. The JSON default parser updates the dictionary while writing, and only the last entry is stored. So I need a way to catch duplicates while parsing, or find a way to store each individual object within data during the json.loads function — Rodney
– Rodney, Commented Aug 16, 2018 at 13:58
@SimonBrahan I think that the Counter solution found here is on the right track, but instead of rejecting the keys, I need to find a way to keep track of each of them. — Rodney
– Rodney, Commented Aug 16, 2018 at 14:06

Pieter De Clercq · Accepted Answer · 2018-08-16 14:42:06Z

1

Based upon the answer given to this question: json.loads allows duplicate keys in a dictionary, overwriting the first value , this should work:

import json

testjson = '{"data": {"key1": "val", "key2": "val", "key1": "val"}}'


def parse_multimap(ordered_pairs):
    multimap = dict()
    for k, v in ordered_pairs:
        if k in multimap:
            multimap[k].append(v)
        else:
            multimap[k] = [v]
    return multimap

parsed = json.loads(testjson, object_pairs_hook=parse_multimap)

for key in parsed['data'][0]:
    print("Key: {} | Count: {}".format(key, len(parsed['data'][0][key])))

Output:

Key: key2 | Count: 1
Key: key1 | Count: 2

edited Aug 16, 2018 at 14:42

answered Aug 16, 2018 at 14:05

Pieter De Clercq

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2 Comments

Rodney Over a year ago

Because your testjson is in a different format as mine, I just get Counter(('data': 1)). How can I get it to look inside "data" before performing this operation?

Rodney Over a year ago

Perfect. Thank you!

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