parse_wants.py

#!/usr/bin/env python3

import csv
import sys
import json
from pathlib import Path

with Path("./wants.json").open() as f:
    data = json.load(f)

keys = {"cardName", "minOffer", "maxOffer"}
writer = csv.DictWriter(sys.stdout, fieldnames=sorted(keys), dialect='excel-tab')
writer.writeheader()
writer.writerows({k: v for k, v in row.items() if k in keys} for row in data)