python - 在for循环内尝试/Except行为异常

Question

代码:

def ValidateProxy(LIST_PROXIES):
    '''
    Checks if scraped proxies allow HTTPS connection
    '''

    for proxy in LIST_PROXIES:

        print('using', proxy)

        host, port = str(proxy).split(":")

        try:
            resp = requests.get('https://amazon.com', 
                                proxies=dict(https=f'socks5://{host}:{port}'),
                                timeout=6)

        except ConnectionError:
            print(proxy, 'REMOVED')
            LIST_PROXIES.remove(proxy)


    print(len(LIST_PROXIES), 'PROXIES GATHERED')

    if len(LIST_PROXIES) != 0:
        return LIST_PROXIES
    else:
        return None

输入:

['46.4.96.137:1080', '138.197.157.32:1080', '138.68.240.218:1080'.....] #15 proxies

输出:

using 46.4.96.137:1080
46.4.96.137:1080 REMOVED
using 138.68.240.218:1080
138.68.240.218:1080 REMOVED
using 207.154.231.213:1080
207.154.231.213:1080 REMOVED
using 198.199.120.102:1080
198.199.120.102:1080 REMOVED
using 88.198.24.108:1080
88.198.24.108:1080 REMOVED
using 188.226.141.211:1080
188.226.141.211:1080 REMOVED
using 92.222.180.156:1080
92.222.180.156:1080 REMOVED
using 183.233.183.70:1081
183.233.183.70:1081 REMOVED
7 PROXIES GATHERED # len(LIST_PROXIES) == 7, so 8 are removed which are printed above

我的疑问:

为什么print('using', proxy)不会每次都执行？ (因为输入列表有15个项目，该行仅被打印8次)

是否每次都尝试执行，但两个块除外？因为每次REMOVED都打印在控制台上。

我想为每个代理使用类似于print('using', proxy)的功能，如果ConnectionError然后是print(proxy, 'REMOVED')并从列表中删除该代理。

编辑:全输入

['46.4.96.137:1080', '138.197.157.32:1080', '138.68.240.218:1080', '162.243.108.129:1080', '207.154.231.213:1080', '176.9.119.170:1080', '198.199.120.102:1080', '176.9.75.42:1080', '88.198.24.108:1080', '188.226.141.61:1080', '188.226.141.211:1080', '125.124.185.167:38801', '92.222.180.156:1080', '188.166.83.17:1080', '183.233.183.70:1081']

Answer 1

问题是您要遍历LIST_PROXIES并同时从中删除元素。

如果您只想遍历LIST_PROXIES一次，则可以执行以下操作:

def ValidateProxy(LIST_PROXIES):
    index = 0 
    for i in range(len(LIST_PROXIES)):
        proxy = LIST_PROXIES[index]
        print('using', proxy)
        host, port = str(proxy).split(":")
        try:
            resp = requests.get('https://amazon.com', 
                                proxies=dict(https=f'socks5://{host}:{port}'),
                                timeout=6)
            index += 1
        except ConnectionError:
            print(proxy, 'REMOVED')
            LIST_PROXIES.pop(index) # Index is not incremented
    print(len(LIST_PROXIES), 'PROXIES GATHERED')
    if len(LIST_PROXIES) != 0:
        return LIST_PROXIES
    else:
        return None

但是，如果两次遍历列表都不成问题，您可以复制列表，如Sy Ker所指出的那样。