Python 爬虫入门

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我是靠谱客的博主神勇高山，这篇文章主要介绍Python 爬虫入门，现在分享给大家，希望可以做个参考。

爬取整个网页

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from urllib2 import urlopen
html = urlopen('网页URL')
print(html.read())

使用BeautifulSoup获取网页指定标签

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from urllib2 import urlopen
from bs4 import BeautifulSoup
html = urlopen('网页URL')
bs = BeautifulSoup(html.read(), 'html.parser')
print(bs.h1)
#打印该网页的H1标签

异常处理

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from urllib2 import urlopen, HTTPError
try:
html = urlopen('网页URL')
except HTTPError as e:
#捕获HTTP异常(404,500)
print(e)
except URLError as e:
#捕获服务器异常(Server not found)
print(e)
else:
print(html.read())

BeautifulSoup的find()和findAll()

findAll(tag , attributes , recursive , text , limit , keywords)

find(tag , attributes , recursive , text , keywords)

例:

.findAll(['h1' , 'h2' , 'h3'])	查找所有H1 , H2 , H3 标签
.findAll('span',{'class':{'green' , 'red'}})	查找所有class为green或red的span标签
abcList = bs.findAll(text='abc') print(len(abcList))	查找'abc'一共出现过几次
.findAll(id='title',class_='text')	查找所有class为text，id为title的标签
.findAll(id='title') == .findAll(' ' , {'id':'title'})
.findAll(class_='red') == .findAll(' ' , {'class':'red'})