网络爬虫之爬取百度新闻链接

1.安装beauitfulsoup4  cmd-> pip install beautifulsoup4
python提供了一个支持处理网络链接的内置模块urllib,beatuifulsoup是用来解析html

 验证安装是否成功

2. pycharm配置

 3.代码如下

import urllib.request
from bs4 import BeautifulSoup
class Scraper:
    def __init__(self,site):
        self.site=site

    def scrape(self):
        r=urllib.request.urlopen(self.site)
        html=r.read()
        parser="html.parser"
        sp=BeautifulSoup(html,parser)
        for tag in sp.find_all("a"):
            url=tag.get("href")
            if url is None:
                continue
            if "html" in url:
                print("
"+url)

news="http://news.baidu.com/"
Scraper(news).scrape()


4.运行结果就是获取了百度新闻的链接

5. 如何把获取的链接保存到文件里呢？

import urllib.request
from bs4 import BeautifulSoup


class Scraper:
    def __init__(self, site):
        self.site = site

    def scrape(self):
        response = urllib.request.urlopen(self.site)
        html = response.read()
        soup = BeautifulSoup(html, 'html.parser')
        with open("output.txt", "w") as f:
            for tag in soup.find_all('a'):
                url = tag.get('href')
                if url and 'html' in url:
                    print("
" + url)
                    f.write(url + "
")

Scraper('http://news.baidu.com/').scrape()