json-flattener

0.2.0 verified Mon Apr 27 auth: no python

Python library for denormalizing nested dicts or JSON objects to tabular form (CSV, TSV, Excel) and back. Current version 0.2.0, with a new poetry-based build and improved error handling. Maintained by the OBO Foundry community. Releases are occasional.

pip install json-flattener

Common errors

error ImportError: No module named 'json_flattener' ↓

cause Misspelled package name or not installed.

fix

Install with: pip install json-flattener

error TypeError: flatten() got an unexpected keyword argument 'separator' ↓

cause Use of deprecated argument name 'separator' instead of 'sep'.

fix

Use sep='.' instead of separator='.'

Warnings

gotcha The default separator is '__' (double underscore), not '.'. Many users expect a dot separator. You can customize with the 'sep' argument. ↓

fix Use flatten(nested, sep='.') for dot notation.

gotcha Flattening a list inside a dict creates keys with numeric indices (e.g., 'b__d__0'). This may not match your schema expectations. ↓

fix Post-process keys or use a different flattening library if you need custom list handling.

Imports

JsonFlattener

from json_flattener import JsonFlattener

flatten

wrong

from json_flattener.flatten import flatten

correct

from json_flattener import flatten

flatten is a top-level function, not a submodule

Quickstart

Flatten a nested dictionary to a flat dictionary with dot-separated keys.

from json_flattener import flatten
nested = {'a': 1, 'b': {'c': 2, 'd': [3, 4]}}
flat = flatten(nested)
print(flat)
# Output: {'a': 1, 'b__c': 2, 'b__d__0': 3, 'b__d__1': 4}