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  • 网络爬虫基础练习

    0.可以新建一个用于练习的html文件,在浏览器中打开。

    0329.html

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Simple DOM Demo</title>
    </head>
    
    <body>
        <h1>This is the document body</h1>
        <P ID = "p1Node">This is paragraph 1.</P>
        <P ID = "p2Node">段落2</P>
        <a href="http://www.gzcc.cn/">广州商学院</a>
    
        <li>
            <a href="http://news.gzcc.cn/html/2018/xiaoyuanxinwen_0328/9113.html">
                <div class="news-list-text">
                    <div class="news-list-title" style="">我校校长杨文轩教授讲授新学期“思政第一课”</div>
                    <div class="news-list-description">3月27日下午,我校校长杨文轩教授在第四教学楼310室为学生讲授了新学期“思政第一课”。</div>
                    <div class="news-list-info"><span><i class="fa fa-clock-o"></i>2018-03-28</span><span><i class="fa fa-building-o"></i>马克思主义学院</span></div>
                </div>
            </a>
        </li>
    </body>
    </html>
    

    1.利用requests.get(url)获取网页页面的html文件

    import requests

    newsurl='http://news.gzcc.cn/html/xiaoyuanxinwen/'

    res = requests.get(newsurl) #返回response对象

    res.encoding='utf-8'

    import requests
    
    newsurl = 'http://news.gzcc.cn/html/xiaoyuanxinwen/'
    
    res = requests.get(newsurl)  # 返回response对象
    
    res.encoding = 'utf-8'
    print(res.text)
    

     

    2.利用BeautifulSoup的HTML解析器,生成结构树

    from bs4 import BeautifulSoup

    soup = BeautifulSoup(res.text,'html.parser')

    from bs4 import BeautifulSoup
     
    soup = BeautifulSoup(res.text,'html.parser')
    

    3.找出特定标签的html元素

    soup.p #标签名,返回第一个

    soup.head

    soup.p.name #字符串

    soup.p. attrs #字典,标签的所有属性

    soup.p. contents # 列表,所有子标签

    soup.p.text #字符串

    soup.p.string

    soup.select(‘li')

    print(soup.body.div.div)
    print(soup.body.div.div.contents)
    print(soup.head)
    print(soup.head.text)
    print(soup.select('li'))
    

    4.取得含有特定CSS属性的元素

    soup.select('#p1Node')

    soup.select('.news-list-title')

    print(soup.select('.container'))
    print(soup.select('#top'))

    5.练习:

    取出h1标签的文本

    import requests
    from bs4 import BeautifulSoup
    newsurl = 'http://localhost:8080/329.html'
    res = requests.get(newsurl)
    res.encoding = 'utf-8'
    res.text
    soup = BeautifulSoup(res.text,'html.parser')
     
    a=soup.select('h1')
    a1=a[0].text
    print(a1)
    


    取出a标签的链接

    a = soup.a.attrs['href']
    soup.li.a.attrs['href']
    print(a)
    


    取出所有li标签的所有内容

    a=soup.select('li')[0].text
    print(a)


    取出一条新闻的标题、链接、发布时间、来源

    a0=soup.select('.news-list-title')[0].text
    a1=soup.select('.news-list-info')[0].contents[0].text
    a2=soup.select('.news-list-info')[0].contents[1].text
    a3=soup.body.li.a.attrs['href']
    print(a0,a1,a2,a3)
    

     

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  • 原文地址:https://www.cnblogs.com/ldg-01/p/8672475.html
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