gdrive.py

# pip install google-api-python-client

from apiclient.discovery import build
from httplib2 import Http
from oauth2client import file, client, tools

SCOPES = 'https://www.googleapis.com/auth/spreadsheets'
store = file.Storage('credentials.json')
creds = store.get()
if not creds or creds.invalid:
    flow = client.flow_from_clientsecrets('client_secret.json', SCOPES)
    creds = tools.run_flow(flow, store)
service = build('sheets', 'v4', http=creds.authorize(Http()))

def get_sheet(sheet_id, range_str):
    result = service.spreadsheets().values().get(spreadsheetId=sheet_id,
                                                 range=range_str).execute()
    rows = result.get('values', [])
    fieldnames = rows[0]
    return [{fieldnames[i]:col for i, col in enumerate(row)} for row in rows[1:]]

def update_sheet(sheet_id, range_str, rows, fieldnames=None):
    fieldnames = list(rows[0].keys()) if not fieldnames else fieldnames
    values = [fieldnames] + [[row.get(col, '') for col in fieldnames] for row in rows]
    body = {'values': values}
    result = service.spreadsheets().values().update(spreadsheetId=sheet_id,
                                                    range=range_str,
                                                    valueInputOption="USER_ENTERED",
                                                    body=body).execute()
    return result

if __name__ == "__main__":
    FILE_ID="xyz"
    rows = get_sheet(FILE_ID, 'output!A:C')
    rows[0]['col1'] = 'changed222222222!'
    result = update_sheet(FILE_ID, 'output!A:C', rows)
    print(result)