Google Distance Matrix API

import googlemaps
import os
import csv
from collections import defaultdict

gmaps = googlemaps.Client(key="AIzaSyDTTdbk89S3Ic####################")
columns = defaultdict(list)

with open('C:/Users/xzhang10/Desktop/ZXY/Dissertation/Data/Dataset/Park_large/output0.csv', 'w') as csvfile:
    spamwriter = csv.writer(csvfile)
    spamwriter.writerow(['Barcode', 'Distance', 'Duration'])
    for dirpath, dirnames, files in os.walk("C:/Users/#########/Data/Dataset/Park_large"):

        for f in files:
            if f.endswith('ParksToBMI.csv'):
                fullpath = os.path.join(dirpath, f)
                print(fullpath)
                with open(fullpath) as csvfile:
                    reader = csv.DictReader(csvfile)  # read rows into a dictionary format
                    for row in reader:  # read a row as {column1: value1, column2: value2,...}
                        for (k, v) in row.items():  # go over each column name and value
                            columns[k].append(v)  # append the value into the appropriate list
                            # based on column name k

                print(columns['Barcode'])
                print(columns['Lat'])
                print(columns['Lon'])
                print(columns['Lat_Park'])
                print(columns['Lon_Park'])

        for i in range(1000,1001):
            origin_lat = columns['Lat'][i]
            origin_lon = columns['Lon'][i]
            des_lat = columns['Lat_Park'][i]
            des_lon = columns['Lon_Park'][i]

            origin_coor = origin_lat + "," + origin_lon
            des_coor = des_lat + "," + des_lon

            matrix = gmaps.distance_matrix(origins=origin_coor, destinations=des_coor, mode="walking")

            distance = matrix['rows'][0]['elements'][0]['distance']
            duration = matrix['rows'][0]['elements'][0]['duration']

            spamwriter.writerow([str(columns['Barcode'][i]),str(distance['text']),str(duration['text'])])
csvfile.close()

i=0