While循环停止工作，但进程继续在python中运行

Question

我使用Python中的while循环来下载csv文件给出的几个pdf文档。代码运行顺利，没有任何问题，但循环在几个循环后停止工作(有时是100次，有时是40次或140次)。

下面是我的代码用于:

import pandas as pd
import os
import urllib
from urllib import request
import requests
import csv
import numpy as np
df = pd.read_csv('Linklist.csv', sep = ';') # can also index sheet by name or fetch all sheets
df.head() #get relevant columns
url_list = df['URL'].tolist() #column with links
name_list = df['Name'].tolist() #column with name
name_list_2 =df['Year'].to_list() #column with second identifier here a year for example
Year_date = []
for element in name_list_2:
Year_date.append(str(element))

max_length = len(url_list)
i = 0
f = open('results.csv', 'w')
writer = csv.writer(f)
while i <= max_length-1:
response = requests.get(url_list[i])
opener =      urllib.request.build_opener()
opener.addheaders = [('User-Agent', 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.0 Safari/605.1.15')]

if response.status_code != 200:
i += 1
a = str(response.status_code)
write_a = (name_list[i], Year_date[i], a)
writer.writerow(write_a)
print(name_list[i]+' '+ Year_date[i]+ ' ' +a)
else:
urllib.request.install_opener(opener)
request.urlretrieve( url_list[i],'/targetpath/'+ name_list[i] + Year_date[i] + '.pdf') #.pdf if it is a pdf doc you want to download
b = str(response.status_code)
write_b = (name_list[i], Year_date[i], b)
writer.writerow(write_b)
print(name_list[i]+' '+ Year_date[i] + ' '+ b)
i += 1
f.close()

Answer 1

@barmar和@ogdenkev的信息是正确的，我需要集成一个Timeout组件!工作代码现在看起来像这样(只是集成了我更改的部分):

DEFAULT_TIMEOUT = 180
old_send = requests.Session.send
def new_send(*args, **kwargs):
if kwargs.get("timeout", None) is None:
kwargs["timeout"] = DEFAULT_TIMEOUT
return old_send(*args, **kwargs)
requests.Session.send = new_send
headers = {'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.0 Safari/605.1.15'}
while i <= max_length-1:
try:
response = requests.get(url_list[I], headers = headers)
opener = urllib.request.build_opener()
opener.addheaders = [('User-Agent', 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.0 Safari/605.1.15')]
if response.status_code != 200:
a = str(response.status_code)
write_a = (name_list[i], Year_date[i], a)
writer.writerow(write_a)
print(name_list[i]+' '+ Year_date[i]+ ' ' +a)
print(i)
i += 1
else:
urllib.request.install_opener(opener)
request.urlretrieve( url_list[i],'/path/'+ name_list[i] + Year_date[i] + '.pdf') #.pdf if it is a pdf doc you want to download
b = str(response.status_code)
write_b = (name_list[i], Year_date[i], b)
writer.writerow(write_b)
print(name_list[i]+' '+ Year_date[i] + ' '+ b)
print(i)
i += 1
except requests.exceptions.RequestException as e:
c = 'Timeout'
write_a = (name_list[i], Year_date[i], c)
writer.writerow(write_a)
print(name_list[i]+' '+ Year_date[i]+ ' ' +c)
print(i)
i += 1
f.close()