我正试图进入一个网页，获取每一行的href/链接。
目前，代码只是打印空白。
预期输出是打印网页中每一行的href/链接。
import requests
from bs4 import BeautifulSoup
url = 'https://meetings.asco.org/meetings/2022-gastrointestinal-cancers-symposium/286/program-guide/search?q=&pageNumber=1&size=20'
baseurl='https://ash.confex.com/ash/2021/webprogram/'
res = requests.get(url)
soup = BeautifulSoup(res.content,'html.parser')
productlist = soup.find_all('div',class_='session-card')
for b in productlist:
links = b["href"]
print(links)
会发生什么
首先，仔细看看你的汤，你不会找到你搜索的信息，因为你会被屏蔽。
此外，您选择的find_all('div',class_='session-card')中的元素没有直接属性href。
如何修复
在您的请求中添加一些标题：
headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36'}
res = requests.get(url, headers=headers)
在迭代中额外选择<a>以选择链接并获得href:
b.a["href"]
示例
import requests
from bs4 import BeautifulSoup
headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36'}
url = 'https://meetings.asco.org/meetings/2022-gastrointestinal-cancers-symposium/286/program-guide/search?q=&pageNumber=1&size=20'
baseurl='https://ash.confex.com/ash/2021/webprogram/'
res = requests.get(url, headers=headers)
soup = BeautifulSoup(res.content,'html.parser')
for b in soup.find_all('div',class_='session-card'):
links = b.a["href"]
print(links)