gistfile1.py

import os
import csv
import json
import collections
from collections import defaultdict



filename = r"C:\Users\zeffi\Desktop\kooo\...\....worldcities.csv"


def open_csv_test(filename):
    #csvfile = open(filename, 'r', encoding='ISO-8859-15', newline='')
    csvfile = open(filename, 'r', encoding='ISO-8859-15', newline='')
    ofile = csv.reader(csvfile, delimiter=',')

    with open(r'C:\Users\zeffi\Desktop\kooo\...\....\worldcities_redux.csv', 'w') as wfile:

        next(ofile)
        for i, row in enumerate(ofile):
            if row[4]:
                if int(row[4]) > 500000:
                    # wfile.write("%s,%s,%s\n" % tuple(row[4:]))
                    wfile.write("{0:1d},{1:.3f},{2:.3f}\n".format(int(int(row[4])/1000), float(row[5]), float(row[6])))

open_csv_test(filename)