Valueerror error: I/O Operation on closed file. when generating csv with python

Question

My code is giving error of "ValueError: I/O operation on closed file."

and I can’t find it in any forum, does anyone know what it might be ? Thank you.

import json
import requests
import csv

url = 'https://api.suthubservice.com/v0/sales' 
headers = {'Content-Type' : 'application/json', 
 'api_key' : 'eb9484921d678843bbfdd6bf460a1df7' 
} 
response = requests.get(url, headers=headers) 
res = json.loads(response.text)

output = []

for contract in res['response']: # tomei a liberdade de mudar o nome da variável
     if len(contract['policies']) > 0:
         for profile in contract['policies'][0]['covered_goods']:
             output.append(profile['Nome'])

totais = {x:output.count(x) for x in output}

with open('C:\Desafio\cadastro.csv', 'r+', newline='') as csvfile:
    spamwriter = csv.writer(csvfile, delimiter=';')
    spamwriter.writerow(['nome_pet'] + ['contador'])


for nome,qtde in totais.items():
    spamwriter.writerow([nome]+[qtde])


for nome,qtde in totais.items():
    print(nome,qtde)

Answer 1

This mistake happens because at the end of with: open(...) as csvfile: the open file is closed. Then soon after you enter a for who tries to write to this file that has already been closed.

Put this on for within the with. Thus:

with open('C:\Desafio\cadastro.csv', 'r+', newline='') as csvfile: 
    spamwriter = csv.writer(csvfile, delimiter=';') 
    spamwriter.writerow(['nome_pet'] + ['contador']) 
    for nome,qtde in totais.items(): 
        spamwriter.writerow([nome]+[qtde])