如何用正则表达式过滤Python列表中仅含v.redd.it域名的URL

针对你的需求，优先推荐不需要正则的实现方案，逻辑更简单，更适合新手掌握：

# 原始URL列表，注意Python中字符串需要用引号包裹
url_list = [
    "https://www.reddit.com/r/funnyvideos/comments/qfvclx/winners_of_the_rfunnyvideos_oscars_2021/",
    "https://v.redd.it/5tmm5wx5lgz71",
    "https://v.redd.it/n35a5fo8cez7",
    "https://v.redd.it/3j0sexqs8ez71",
    "https://v.redd.it/cmy0l1roxfz71"
]

required_urls = []
excluded_urls = []
for url in url_list:
    # 直接用in运算符判断是否包含目标子串即可
    if "v.redd.it/" in url:
        required_urls.append(url)
    else:
        excluded_urls.append(url)

# 按你要求的格式输出结果
print("Your required urls :\n")
for url in required_urls:
    print(f"  {url},")
print("\nExcluded Urls :\n")
for url in excluded_urls:
    print(f"  {url}")

如果你需要练习正则表达式的使用，也可以用以下实现，注意正则中.是特殊匹配符，需要加反斜杠转义才能匹配实际的点号：

import re

url_list = [
    "https://www.reddit.com/r/funnyvideos/comments/qfvclx/winners_of_the_rfunnyvideos_oscars_2021/",
    "https://v.redd.it/5tmm5wx5lgz71",
    "https://v.redd.it/n35a5fo8cez7",
    "https://v.redd.it/3j0sexqs8ez71",
    "https://v.redd.it/cmy0l1roxfz71"
]

required_urls = []
excluded_urls = []
# 定义正则匹配规则
pattern = r"v\.redd\.it/"
for url in url_list:
    if re.search(pattern, url):
        required_urls.append(url)
    else:
        excluded_urls.append(url)

# 输出部分和上述方案一致
print("Your required urls :\n")
for url in required_urls:
    print(f"  {url},")
print("\nExcluded Urls :\n")
for url in excluded_urls:
    print(f"  {url}")

内容的提问来源于stack exchange，提问作者Sainita