Little script to convert JSON to CSV

json2csv.py

from sys import argv
from json import load
from csv import DictWriter
from os.path import exists


filename = 'json.json'

if len(argv) > 1:
    filename = argv[1]

with open(filename, 'r', encoding='utf-8') as file:
    json_objs = load(file)

filename_csv = filename.split('.')[0] + '.csv'
write_headers = not exists(filename_csv)
headers = []
for obj in json_objs:
    headers.extend(obj.keys())
headers = sorted(set(headers))

with open(filename_csv, 'a+', encoding='utf-8', newline='') as file:
    writer = DictWriter(file, fieldnames=headers)
    if write_headers:
        writer.writeheader()
    writer.writerows(json_objs)