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。

<!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>

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)
res.encoding='utf-8'

2.利用BeautifulSoup的HTML解析器，生成结构树

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

3.找出特定标签的html元素

soup.p
soup.head
soup.p.name
soup.p.attrs
soup.p.contents
soup.p.text
soup.p.string
soup.select('li')

4.取得含有特定CSS属性的元素

soup.select('#p1Node')
soup.select('.news-list-title')

5.练习：

取出h1标签的文本

import requests
from bs4 import BeautifulSoup
url = 'http://localhost:63342/draw/venv/329.html?_ijt=nf522vm6pmjoqqg6p6nfqp03rf'
res =requests.get(url)
res.encoding='utf-8'
res.text
soup = BeautifulSoup(res.text,'html.parser')
a=soup.select('h1')[0].text
print(a)

取出a标签的链接

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

 


取出所有li标签的所有内容

for b in soup.select('li'):
    print(b)

 


取出一条新闻的标题、链接、发布时间、来源

print(soup.select('.news-list-title')[0].text)
print(soup.body.li.a.attrs['href'])
print(soup.select('.news-list-info')[0].contents[0].text)
print(soup.select('.news-list-info')[0].contents[1].text)

 

posted on 2018-03-30 17:56  249伍思敏  阅读(125)  评论(0)  编辑  收藏  举报

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