当前位置:  开发笔记 > 编程语言 > 正文

python利用beautifulSoup实现爬虫

这篇文章主要介绍了python利用beautifulSoup实现爬虫,需要的朋友可以参考下

以前讲过利用phantomjs做爬虫抓网页 https://www.jb51.net/article/55789.htm 是配合选择器做的

利用 beautifulSoup(文档 :http://www.crummy.com/software/BeautifulSoup/bs4/doc/)这个python模块,可以很轻松的抓取网页内容

# coding=utf-8
import urllib
from bs4 import BeautifulSoup

url ='http://www.baidu.com/s'
values ={'wd':'网球'}
encoded_param = urllib.urlencode(values)
full_url = url +'?'+ encoded_param
response = urllib.urlopen(full_url)
soup =BeautifulSoup(response)
alinks = soup.find_all('a')

上面可以抓取百度搜出来结果是网球的记录。

beautifulSoup内置了很多非常有用的方法。

几个比较好用的特性:

构造一个node元素

复制代码 代码如下:

soup = BeautifulSoup('Extremely bold')
tag = soup.b
type(tag)
#

属性可以使用attr拿到,结果是字典

复制代码 代码如下:

tag.attrs
# {u'class': u'boldest'}

或者直接tag.class取属性也可。

也可以自由操作属性

tag['class'] = 'verybold'
tag['id'] = 1
tag
# 
Extremely bold
del tag['class'] del tag['id'] tag #
Extremely bold
tag['class'] # KeyError: 'class' print(tag.get('class')) # None

还可以随便操作,查找dom元素,比如下面的例子

1.构建一份文档

html_doc = """
<html><head><title>The Dormouse's story</title></head>

<p><b>The Dormouse's story</b></p>

<p>Once upon a time there were three little sisters; and their names were
<a href="http://example.com/elsie" id="link1">Elsie</a>,
<a href="http://example.com/lacie" id="link2">Lacie</a> and
<a href="http://example.com/tillie" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>

<p>...</p>
"""

from bs4 import BeautifulSoup
soup = BeautifulSoup(html_doc)

2.各种搞

soup.head
# The Dormouse's story
soup.title
# The Dormouse's story
soup.body.b
# The Dormouse's story
soup.a
# Elsie
soup.find_all('a')
# [Elsie,
# Lacie,
# Tillie]
head_tag = soup.head
head_tag
# The Dormouse's story

head_tag.contents
[The Dormouse's story]

title_tag = head_tag.contents[0]
title_tag
# The Dormouse's story
title_tag.contents
# [u'The Dormouse's story']
len(soup.contents)
# 1
soup.contents[0].name
# u'html'
text = title_tag.contents[0]
text.contents

for child in title_tag.children:
  print(child)
head_tag.contents
# [The Dormouse's story]
for child in head_tag.descendants:
  print(child)
# The Dormouse's story
# The Dormouse's story

len(list(soup.children))
# 1
len(list(soup.descendants))
# 25
title_tag.string
# u'The Dormouse's story'
推荐阅读
小妖694_807
这个屌丝很懒,什么也没留下!
DevBox开发工具箱 | 专业的在线开发工具网站    京公网安备 11010802040832号  |  京ICP备19059560号-6
Copyright © 1998 - 2020 DevBox.CN. All Rights Reserved devBox.cn 开发工具箱 版权所有