convert a bunch of json files into a csv file

jsons2csv.py

import argparse
import csv
import json


parser = argparse.ArgumentParser(
    description="""
Convert a number of json files into a single CSV file with each file as a row.""",
    epilog="""
Example:
    
""")

parser.add_argument('csvfile', type=argparse.FileType('w'),
                    help="csv file to generate")
parser.add_argument('jsonfile', nargs='+', type=argparse.FileType('r'),
                    help="json files to parse")

def main():
    args = parser.parse_args()
    data = [json.load(jf) for jf in args.jsonfile]
    keys = sorted(set(k for d in data for k in d ))
    out = csv.DictWriter(args.csvfile, keys, extrasaction='ignore')
    out.writeheader()
    for entry in data:
        out.writerow(entry)

if __name__ == '__main__':
    main()

Now csv writers are context managers you can write

with csv.DictWriter(args.csvfile, keys, extrasaction='ignore') as out:
    out.writeheader()
    for entry in data:
        out.writerow(entry)