python正则提取域名

import re

def extract_domain(url):
    # 定义一个匹配域名的正则表达式
    domain_regex = r'(?:(?:https?|ftp):\/\/)?(?:\S+(?::\S*)?@)?((?:(?!-)[A-Za-z0-9-]{1,63}(?<!-)\.)+[A-Za-z]{2,6})'
    
    # 使用re.search查找匹配的域名
    match = re.search(domain_regex, url)
    
    if match:
        return match.group(1)
    else:
        return None

# 测试示例
urls = [
    "http://www.example.com",
    "https://subdomain.example.co.uk",
    "ftp://user:pass@example.org"
]

for url in urls:
    print(f"URL: {url}, Domain: {extract_domain(url)}")

domain_regex = r'(?:(?:https?|ftp):\/\/)?(?:\S+(?::\S*)?@)?((?:[A-Za-z0-9](?:[A-Za-z0-9-]{0,61}[A-Za-z0-9])?\.)+[A-Za-z]{2,6})'