import requests
from bs4 import BeautifulSoup

爬取url地址

url = 'http://www.example.com'

发送请求，获取响应内容

response = requests.get(url)

把响应内容转换为BeautifulSoup对象，便于提取元素

soup = BeautifulSoup(response.text, 'lxml')

提取所有a标签中的链接地址，并存入列表中

links = [link.get('href') for link in soup.find_all('a')]