Python實戰(zhàn)快速上手BeautifulSoup庫爬取專欄標題和地址

更新時間：2021年10月20日 14:48:50 作者：小旺不正經

BeautifulSoup是爬蟲必學的技能，BeautifulSoup最主要的功能是從網頁抓取數據，Beautiful Soup自動將輸入文檔轉換為Unicode編碼，輸出文檔轉換為utf-8編碼

安裝

pip install beautifulsoup4
# 上面的安裝失敗使用下面的 使用鏡像
pip install beautifulsoup4 -i https://pypi.tuna.tsinghua.edu.cn/simple

使用PyCharm的命令行

解析標簽

from bs4 import BeautifulSoup
import requests
url='https://blog.csdn.net/weixin_42403632/category_11076268.html'
headers={'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:93.0) Gecko/20100101 Firefox/93.0'}
html=requests.get(url,headers=headers).text
s=BeautifulSoup(html,'html.parser')
title =s.select('h2')
for i in title:
    print(i.text)

第一行代碼：導入BeautifulSoup庫

第二行代碼：導入requests

第三、四、五行代碼：獲取url的html

第六行代碼：激活BeautifulSoup庫 'html.parser'設置解析器為HTML解析器

第七行代碼：選取所有<h2>標簽

解析屬性

BeautifulSoup庫支持根據特定屬性解析網頁元素

根據class值解析

from bs4 import BeautifulSoup
import requests
url='https://blog.csdn.net/weixin_42403632/category_11076268.html'
headers={'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:93.0) Gecko/20100101 Firefox/93.0'}
html=requests.get(url,headers=headers).text
s=BeautifulSoup(html,'html.parser')
title =s.select('.column_article_title')
for i in title:
    print(i.text)

根據ID解析

from bs4 import BeautifulSoup
html='''<div class="crop-img-before">
         <img src="" alt="" id="cropImg">
      </div>
        <div id='title'>
        測試成功
        </div>
      <div class="crop-zoom">
         <a href="javascript:;" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  class="bt-reduce">-</a><a href="javascript:;" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  class="bt-add">+</a>
      </div>
      <div class="crop-img-after">
         <div  class="final-img"></div>
      </div>'''
s=BeautifulSoup(html,'html.parser')
title =s.select('#title')
for i in title:
    print(i.text)

多層篩選

from bs4 import BeautifulSoup
html='''<div class="crop-img-before">
         <img src="" alt="" id="cropImg">
      </div>
        <div id='title'>
        456456465
        <h1>測試成功</h1>
        </div>
      <div class="crop-zoom">
         <a href="javascript:;" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  class="bt-reduce">-</a><a href="javascript:;" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  class="bt-add">+</a>
      </div>
      <div class="crop-img-after">
         <div  class="final-img"></div>
      </div>'''
s=BeautifulSoup(html,'html.parser')
title =s.select('#title')
for i in title:
    print(i.text)
title =s.select('#title h1')
for i in title:
    print(i.text)

提取a標簽中的網址

title =s.select('a')
for i in title:
    print(i['href'])

實戰(zhàn)-獲取博客專欄標題+網址

from bs4 import BeautifulSoup
import requests
import re
url='https://blog.csdn.net/weixin_42403632/category_11298953.html'
headers={'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:93.0) Gecko/20100101 Firefox/93.0'}
html=requests.get(url,headers=headers).text
s=BeautifulSoup(html,'html.parser')
title =s.select('.column_article_list li a')
for i in title:
    print((re.findall('原創(chuàng).*?\n(.*?)\n',i.text))[0].lstrip())
    print(i['href'])