json-key-parser 0.0.2

Extract specific keys from JSON objects with recursive search and wildcard matching

json_parser

A lightweight Python library for extracting specific keys from complex, nested JSON structures. Rather than manually traversing deeply nested objects, json_parser lets you declare the keys you care about and recursively retrieves their values — with support for wildcard matching and automatic merging of duplicate keys.

Features

• Key-based extraction — Specify the keys you need and let the parser handle the traversal.
• Wildcard matching — Use glob-style patterns (e.g., address*) to match multiple keys at once.
• Recursive search — Automatically searches through nested dictionaries and lists.
• Duplicate key merging — When the same key appears at multiple levels, values are combined into a list.
• Zero dependencies — Uses only the Python standard library.

Installation

pip install json-key-parser

Or install from source:

git clone https://github.com/diverdale/json_parser.git
cd json_parser
pip install .

Quick Start

import json
from json_parser import JsonParser

json_data = [
    {
        "first_name": "John",
        "last_name": "Doe",
        "full_name": "John Doe",
        "address1": {
            "street": "1208 Elm Street",
            "city": "Springfield",
            "zip_code": "62704"
        },
        "address2": {
            "street": "4965 Harvest Rd",
            "city": "Springfield",
            "zip_code": "62704"
        },
        "birthday": "1984-05-23"
    },
    {
        "first_name": "Jane",
        "last_name": "Smith",
        "full_name": "Jane Smith",
        "address": {
            "street": "742 Evergreen Terrace",
            "city": "Springfield",
            "zip_code": "62701"
        },
        "birthday": "1990-11-12"
    }
]

keys = ["first_name", "last_name", "birthday"]

result = JsonParser(json_data, keys).get_data()
print(json.dumps(result, indent=4))

Output:

[
    {
        "first_name": "John",
        "last_name": "Doe",
        "birthday": "1984-05-23"
    },
    {
        "first_name": "Jane",
        "last_name": "Smith",
        "birthday": "1990-11-12"
    }
]

Wildcard Matching

Use glob-style patterns to match keys dynamically. For example, address* matches address, address1, and address2:

keys = ["first_name", "address*", "birthday"]
result = JsonParser(json_data, keys).get_data()

Output:

[
    {
        "first_name": "John",
        "address1": {
            "street": "1208 Elm Street",
            "city": "Springfield",
            "zip_code": "62704"
        },
        "address2": {
            "street": "4965 Harvest Rd",
            "city": "Springfield",
            "zip_code": "62704"
        },
        "birthday": "1984-05-23"
    },
    {
        "first_name": "Jane",
        "address": {
            "street": "742 Evergreen Terrace",
            "city": "Springfield",
            "zip_code": "62701"
        },
        "birthday": "1990-11-12"
    }
]

Duplicate Key Merging

When the same key is found at multiple nesting levels within a single record, the values are automatically combined into a list:

keys = ["first_name", "street", "birthday"]
result = JsonParser(json_data, keys).get_data()

Output:

[
    {
        "first_name": "John",
        "street": [
            "1208 Elm Street",
            "4965 Harvest Rd"
        ],
        "birthday": "1984-05-23"
    },
    {
        "first_name": "Jane",
        "street": "742 Evergreen Terrace",
        "birthday": "1990-11-12"
    }
]

API Reference

JsonParser(obj, args)

Parameter	Type	Description
obj	list[dict]	A list of JSON objects (dicts) to search.
args	list[str]	Key names or glob patterns to extract.

Raises JsonParserException if obj or args is empty.

Methods

Method	Returns	Description
get_data()	list[dict]	Extracts and returns matching key-value pairs from each record.
get_json()	list[dict]	Returns the original JSON input.
get_args()	list[str]	Returns the list of keys/patterns.

Running Tests

pytest tests/

License

This project is licensed under the MIT License. See the LICENSE file for details.