网络爬虫基础练习

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'

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 #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')

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
取出a标签的链接
取出所有li标签的所有内容
取出一条新闻的标题、链接、发布时间、来源

import requests
from bs4 import BeautifulSoup as bs

url = "http://news.gzcc.cn/html/2018/xiaoyuanxinwen_0329/9122.html"
res = requests.get(url).content.decode('utf-8')
soup = bs(res, 'html.parser')
h1 = soup.select('h1')[0].get_text()
print(h1)

a = soup.select('a')
for href in a:
print(href.get('href'))

li = soup.select('li')
for l in li:
print(l.get_text())

title = soup.select('title')
print(title)

url = 'http://news.gzcc.cn/html/xiaoyuanxinwen/'
res = requests.get(url).content.decode('utf-8')
soup = bs(res, 'html.parser')
h = soup.select('.news-list li a')
for i in h:
print(i[0].get('href'))
print(i[1].get_text())