import csv import json csvfile = open('DE.txt', 'r') jsonfile = open('de.json', 'w') fieldnames = ("countryCode","postalCode","placeName","adminName1","adminCode1","adminName2","adminCode2","adminName3","adminCode3","latitude","longitude","accuracy") reader = csv.DictReader(csvfile, fieldnames, delimiter='\t') jsonfile.write("{ \"docs\": [") for row in reader: lat = row["latitude"] lon = row["longitude"] row.pop("latitude") row.pop("longitude") row["loc"] = [float(lon), float(lat)] json.dump(row, jsonfile) jsonfile.write(",\n") jsonfile.write("]}")