web爬虫，BeautifulSoup

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BeautifulSoup

该模块用于接收一个html或XML字符串，然后将其进行格式化，之后遍可以使用他提供的方法进行快速查找指定元素，从而使得在HTML或XML中查找指定元素变得简单。

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from bs4 import BeautifulSoup
 
html_doc = """
<html><head><title>The Dormouse\'s story</title></head>
<body>
asdf
    <div class="title">
        <b>The Dormouse\'s story总共</b>
        <h1>f</h1>
    </div>
<div class="story">Once upon a time there were three little sisters; and their names were
    <a  class="sister0" id="link1">Els<span>f</span>ie</a>,
    <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
    <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.</div>
ad<br/>sf
<p class="story">...</p>
</body>
</html>
"""
 
soup = BeautifulSoup(html_doc, features="lxml")
# 找到第一个a标签
tag1 = soup.find(name=\'a\')
# 找到所有的a标签
tag2 = soup.find_all(name=\'a\')
# 找到id＝link2的标签
tag3 = soup.select(\'#link2\')

使用示例：

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from bs4 import BeautifulSoup
 
html_doc = """
<html><head><title>The Dormouse\'s story</title></head>
<body>
    ...
</body>
</html>
"""
 
soup = BeautifulSoup(html_doc, features="lxml")

1. name，标签名称

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# tag = soup.find(\'a\')
# name = tag.name # 获取
# print(name)
# tag.name = \'span\' # 设置
# print(soup)

2. attr，标签属性

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# tag = soup.find(\'a\')
# attrs = tag.attrs    # 获取
# print(attrs)
# tag.attrs = {\'ik\':123} # 设置
# tag.attrs[\'id\'] = \'iiiii\' # 设置
# print(soup)

3. children,所有子标签

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# body = soup.find(\'body\')
# v = body.children

4. children,所有子子孙孙标签

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# body = soup.find(\'body\')
# v = body.descendants

5. clear,将标签的所有子标签全部清空（保留标签名）

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# tag = soup.find(\'body\')
# tag.clear()
# print(soup)

6. decompose,递归的删除所有的标签

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# body = soup.find(\'body\')
# body.decompose()
# print(soup)

7. extract,递归的删除所有的标签，并获取删除的标签

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# body = soup.find(\'body\')
# v = body.extract()
# print(soup)

8. decode,转换为字符串（含当前标签）；decode_contents（不含当前标签）

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# body = soup.find(\'body\')
# v = body.decode()
# v = body.decode_contents()
# print(v)

9. encode,转换为字节（含当前标签）；encode_contents（不含当前标签）

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# body = soup.find(\'body\')
# v = body.encode()
# v = body.encode_contents()
# print(v)

10. find,获取匹配的第一个标签

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# tag = soup.find(\'a\')
# print(tag)
# tag = soup.find(name=\'a\', attrs={\'class\': \'sister\'}, recursive=True, text=\'Lacie\')
# tag = soup.find(name=\'a\', class_=\'sister\', recursive=True, text=\'Lacie\')
# print(tag)

11. find_all,获取匹配的所有标签

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# tags = soup.find_all(\'a\')
# print(tags)
 
# tags = soup.find_all(\'a\',limit=1)
# print(tags)
 
# tags = soup.find_all(name=\'a\', attrs={\'class\': \'sister\'}, recursive=True, text=\'Lacie\')
# # tags = soup.find(name=\'a\', class_=\'sister\', recursive=True, text=\'Lacie\')
# print(tags)
 
 
# ####### 列表 #######
# v = soup.find_all(name=[\'a\',\'div\'])
# print(v)
 
# v = soup.find_all(class_=[\'sister0\', \'sister\'])
# print(v)
 
# v = soup.find_all(text=[\'Tillie\'])
# print(v, type(v[0]))
 
 
# v = soup.find_all(id=[\'link1\',\'link2\'])
# print(v)
 
# v = soup.find_all(href=[\'link1\',\'link2\'])
# print(v)
 
# ####### 正则 #######
import re
# rep = re.compile(\'p\')
# rep = re.compile(\'^p\')
# v = soup.find_all(name=rep)
# print(v)
 
# rep = re.compile(\'sister.*\')
# v = soup.find_all(class_=rep)
# print(v)
 
# rep = re.compile(\'http://www.oldboy.com/static/.*\')
# v = soup.find_all(href=rep)
# print(v)
 
# ####### 方法筛选 #######
# def func(tag):
# return tag.has_attr(\'class\') and tag.has_attr(\'id\')
# v = soup.find_all(name=func)
# print(v)
 
 
# ## get,获取标签属性
# tag = soup.find(\'a\')
# v = tag.get(\'id\')
# print(v)

12. has_attr,检查标签是否具有该属性

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# tag = soup.find(\'a\')
# v = tag.has_attr(\'id\')
# print(v)

13. get_text,获取标签内部文本内容

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# tag = soup.find(\'a\')
# v = tag.get_text
# print(v)

14. index,检查标签在某标签中的索引位置

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# tag = soup.find(\'body\')
# v = tag.index(tag.find(\'div\'))
# print(v)
 
# tag = soup.find(\'body\')
# for i,v in enumerate(tag):
# print(i,v)

15. is_empty_element,是否是空标签(是否可以是空)或者自闭合标签，

     判断是否是如下标签：\'br\' , \'hr\', \'input\', \'img\', \'meta\',\'spacer\', \'link\', \'frame\', \'base\'

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# tag = soup.find(\'br\')
# v = tag.is_empty_element
# print(v)

16. 当前的关联标签

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# soup.next
# soup.next_element
# soup.next_elements
# soup.next_sibling
# soup.next_siblings
 
#
# tag.previous
# tag.previous_element
# tag.previous_elements
# tag.previous_sibling
# tag.previous_siblings
 
#
# tag.parent
# tag.parents

17. 查找某标签的关联标签

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# tag.find_next(...)
# tag.find_all_next(...)
# tag.find_next_sibling(...)
# tag.find_next_siblings(...)
 
# tag.find_previous(...)
# tag.find_all_previous(...)
# tag.find_previous_sibling(...)
# tag.find_previous_siblings(...)
 
# tag.find_parent(...)
# tag.find_parents(...)
 
# 参数同find_all

18. select,select_one, CSS选择器

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soup.select("title")
 
soup.select("p nth-of-type(3)")
 
soup.select("body a")
 
soup.select("html head title")
 
tag = soup.select("span,a")
 
soup.select("head > title")
 
soup.select("p > a")
 
soup.select("p > a:nth-of-type(2)")
 
soup.select("p > #link1")
 
soup.select("body > a")
 
soup.select("#link1 ~ .sister")
 
soup.select("#link1 + .sister")
 
soup.select(".sister")
 
soup.select("[class~=sister]")
 
soup.select("#link1")
 
soup.select("a#link2")
 
soup.select(\'a[href]\')
 
soup.select(\'a[href="http://example.com/elsie"]\')
 
soup.select(\'a[href^="http://example.com/"]\')
 
soup.select(\'a[href$="tillie"]\')
 
soup.select(\'a[href*=".com/el"]\')
 
 
from bs4.element import Tag
 
def default_candidate_generator(tag):
    for child in tag.descendants:
        if not isinstance(child, Tag):
            continue
        if not child.has_attr(\'href\'):
            continue
        yield child
 
tags = soup.find(\'body\').select("a", _candidate_generator=default_candidate_generator)
print(type(tags), tags)
 
from bs4.element import Tag
def default_candidate_generator(tag):
    for child in tag.descendants:
        if not isinstance(child, Tag):
            continue
        if not child.has_attr(\'href\'):
            continue
        yield child
 
tags = soup.find(\'body\').select("a", _candidate_generator=default_candidate_generator, limit=1)
print(type(tags), tags)

19. 标签的内容

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# tag = soup.find(\'span\')
# print(tag.string)          # 获取
# tag.string = \'new content\' # 设置
# print(soup)
 
# tag = soup.find(\'body\')
# print(tag.string)
# tag.string = \'xxx\'
# print(soup)
 
# tag = soup.find(\'body\')
# v = tag.stripped_strings  # 递归内部获取所有标签的文本
# print(v)

20.append在当前标签内部追加一个标签

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# tag = soup.find(\'body\')
# tag.append(soup.find(\'a\'))
# print(soup)
#
# from bs4.element import Tag
# obj = Tag(name=\'i\',attrs={\'id\': \'it\'})
# obj.string = \'我是一个新来的\'
# tag = soup.find(\'body\')
# tag.append(obj)
# print(soup)

21.insert在当前标签内部指定位置插入一个标签

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# from bs4.element import Tag
# obj = Tag(name=\'i\', attrs={\'id\': \'it\'})
# obj.string = \'我是一个新来的\'
# tag = soup.find(\'body\')
# tag.insert(2, obj)
# print(soup)

22. insert_after,insert_before 在当前标签后面或前面插入

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# from bs4.element import Tag
# obj = Tag(name=\'i\', attrs={\'id\': \'it\'})
# obj.string = \'我是一个新来的\'
# tag = soup.find(\'body\')
# # tag.insert_before(obj)
# tag.insert_after(obj)
# print(soup)

23. replace_with 在当前标签替换为指定标签

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# from bs4.element import Tag
# obj = Tag(name=\'i\', attrs={\'id\': \'it\'})
# obj.string = \'我是一个新来的\'
# tag = soup.find(\'div\')
# tag.replace_with(obj)
# print(soup)

24. 创建标签之间的关系

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# tag = soup.find(\'div\')
# a = soup.find(\'a\')
# tag.setup(previous_sibling=a)
# print(tag.previous_sibling)

25. wrap，将指定标签把当前标签包裹起来

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# from bs4.element import Tag
# obj1 = Tag(name=\'div\', attrs={\'id\': \'it\'})
# obj1.string = \'我是一个新来的\'
#
# tag = soup.find(\'a\')
# v = tag.wrap(obj1)
# print(soup)
 
# tag = soup.find(\'a\')
# v = tag.wrap(soup.find(\'p\'))
# print(soup)

26. unwrap，去掉当前标签，将保留其包裹的标签

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# tag = soup.find(\'a\')
# v = tag.unwrap()
# print(soup)

更多参数官方：http://beautifulsoup.readthedocs.io/zh_CN/v4.4.0/

 

五、示例

把下面代码，加入到代码中，可以下载网站源码到本地分析

with open(\'weixin.html\',\'wb\') as f:
    f.write(wx_login_page.content)

1、爬取汽车之家新闻频道页面里面的图片

复制代码
#!/usr/bin/env python
# -*- coding:utf-8 -*- 
# Author: nulige

import requests
from bs4 import BeautifulSoup

response = requests.get(
    url=\'http://www.autohome.com.cn/news/\'
)

#解决爬虫乱码问题
response.encoding = response.apparent_encoding  

# 生成Soup对象，
soup = BeautifulSoup(response.text, features=\'html.parser\')


# find查找第一个符合条件的对象
target = soup.find(id=\'auto-channel-lazyload-article\')

#find_all查找所有符合的对象，查找出来的值在列表中
li_list = target.find_all(\'li\')

#循环拿到具体每个对象
for i in li_list:
    a = i.find(\'a\')

    if a:
        print(a.attrs.get(\'href\'))   #    # .attrs查找到属性
        txt = a.find(\'h3\').text  # 是对象
        img_url = a.find(\'img\').attrs.get(\'src\')
        print(img_url)
        # 再发一个请求
        img_response = requests.get(url=img_url)
        import uuid
        file_name = str(uuid.uuid4()) + \'.jpg\'
        with open(file_name,\'wb\') as f:
            f.write(img_response.content)


备注：
　# 找到第一个a标签
　　tag1 = soup.find(name=\'a\')
 
　　# 找到所有的a标签
　　tag2 = soup.find_all(name=\'a\')
 
　　# 找到id＝link2的标签
　　tag3 = soup.select(\'#link2\')
复制代码

2、自动登陆抽屉网

复制代码
#!/usr/bin/env python
# -*- coding: utf8 -*-
# __Author: "Skiler Hao"
# date: 2017/5/10 11:06
import requests
from bs4 import BeautifulSoup

# 第一次请求
first_request_response = requests.get(
    url = \'http://dig.chouti.com/\',
)
# 获取第一次登录获取的cookie内容
firstget_cookie_dict = first_request_response.cookies.get_dict()


# 登录POST请求
post_dict = {
    \'phone\': \'8618811*****\', #86+手机号码
    \'password\': \'******\',    #密码
    \'oneMonth\': 1
}
# 发送请求，携带cookie和数据
login_response = requests.post(
    url = \'http://dig.chouti.com/login\',
    data = post_dict,
    cookies= firstget_cookie_dict
)


# 点赞请求
dianzan_response = requests.post(
    url = \'http://dig.chouti.com/link/vote?linksId=11832246\',
    cookies= firstget_cookie_dict
)
print(dianzan_response.text)


# 取消点赞
cancel_dianzan
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