csv-to-json.py

import json
import sys
import csv


def main(fn):
    with open(fn, 'r', newline='') as csvfile:
        reader = csv.DictReader(csvfile)
        rows = [dict(row) for row in reader]
    with open('data.json', 'w') as jsonfile:
        jsonfile.write(json.dumps(rows, indent=2))


if __name__ == "__main__":
    args = sys.argv
    if len(args) == 2:
        fn = args[1]
    else:
        fn = input('csv filename > ')
    main(fn)

python3 csv-to-json.py my.csv