一、BeautifulSoup的基本使用
from bs4 import BeautifulSoup
from bs4 import SoupStrainer
import re html_doc = """
<html>
<head>
<title>
The Dormouse's story
</title>
</head>
<body>
<p class="title">
<b>
The Dormouse's story
</b>
</p>
<p class="story">
Once upon a time there were three little sisters; and their names were
<a class="sister" href="http://example.com/elsie" id="link1">
Elsie
</a>
,
<a class="sister" href="http://example.com/lacie" id="link2">
Lacie
</a>
and
<a class="sister" href="http://example.com/tillie" id="link3">
Tillie
</a>
; and they lived at the bottom of a well.
</p>
<p class="story">
...
</p>
</body>
</html>
"""
soup = BeautifulSoup(html_doc, "html.parser")
# print(soup.prettify()) # 打印所有标准化html code
print('-----------------------------')
print(soup.title)
print('----------------------------')
print(soup.title.name)
print('----------------------------')
print(soup.title.string)
print('----------------------------')
print(soup.title.parent.name)
print('----------------------------')
print(soup.p)
# item_b = soup.p.
print('----------------------------')
print(soup.p['class'])
print('----------------------------')
print(soup.find_all('a'))
print('----------------------------')
print(soup.find(id='link3'))
print(soup.find(id='link3')['class'])
print(soup.find(id='link3')['href']) # 打印指定属性文本
print(soup.find(id='link3')['id'])
print(soup.find(id='link3').get_text()) # 打印文本 # find_all(name, attrs, recursive, text, limit, **kwargs)
# name 参数
soup.find_all('title') # keyword参数
soup.find_all(id='link2')
soup.find_all(href=re.compile("elsie"))
soup.find_all(id=True) # 在文档树中查找所有包含 id 属性的tag,无论 id 的值是什么
soup.find_all(href=re.compile("elsie"), id='link1') # 多个指定名字的参数可以同时过滤tag的多个属性
soup.find_all(attrs={"data-foo": "value"}) # 可以通过 find_all() 方法的 attrs 参数定义一个字典参数来搜索包含特殊属性的tag:
soup.find_all('a', limit=2) # 当搜索结果到达limit个数，就停止搜索 # 按CSS搜索
soup.find_all("a", class_="sister")
soup.find_all(class_=re.compile("itl")) # class_ 参数同样接受不同类型的 过滤器 ,字符串,正则表达式 # CSS选择器
title_list = soup.select('head > title') # 查找所有满足条件的元素
title_list_one = soup.select_one('head > title') # 查找单个满足条件的元素
print(title_list) # 打印 [<title> The Dormouse's story</title>]
print(title_list[0].string) # 打印The Dormouse's story< # 文档中找到所有<a>标签的链接：
for link in soup.find_all('a'):
print(link.get('href'))
# http://example.com/elsie
# http://example.com/lacie
# http://example.com/tillie # find查找元素第一个类样式未story的p标签
p_story = soup.find('p',class_='story')
# print(p_story.a) # 使用正则表达式
p_re_all = soup.find_all(re.compile('p'))
print(p_re_all) # find_all查找所有class_=True匹配任何类样式的p标签
p_all = soup.find_all('p', class_=True)
# print(p_all) # 打印数组
# [<p class="title">
# <b>
# The Dormouse's story
# </b>
# </p>, <p class="story">
# Once upon a time there were three little sisters; and their names were
# <a class="sister" href="http://example.com/elsie" id="link1">
# Elsie
# </a>
# ,
# <a class="sister" href="http://example.com/lacie" id="link2">
# Lacie
# </a>
# and
# <a class="sister" href="http://example.com/tillie" id="link3">
# Tillie
# </a>
# ; and they lived at the bottom of a well.
# </p>, <p class="story">
# ...
# </p>]
二、BeautifulSoup的实际应用
1.解析网易云音乐html源码
这是网易云音乐华语歌曲的分类链接http://music.163.com/#/discover/playlist/?order=hot&cat=华语&limit=35&offset=0，打开Chrome F12的Elements查看到页面源码，我们发现每页的歌单都在一个iframe浮窗上面，每首单曲的信息构成一个li标签，包含歌单图片、
歌单链接、歌单名称等。
首先提取一段html源码出来
<ul class="m-cvrlst f-cb" id="m-pl-container">
<li>
<div class="u-cover u-cover-1">
<img class="j-flag" src="http://p1.music.126.net/FGe-rVrHlBTbnOvhMR99PQ==/109951162989189558.jpg?param=140y140" />
<a title="【说唱】留住你一面，画在我心间" href="/playlist?id=832790627" class="msk"></a>
<div class="bottom">
<a class="icon-play f-fr" title="播放" href="javascript:;" data-res-type="13" data-res-id="832790627" data-res-action="play"></a>
<span class="icon-headset"></span>
<span class="nb">1615</span>
</div>
</div> <p class="dec"> <a title="【说唱】留住你一面，画在我心间" href="/playlist?id=832790627" class="tit f-thide s-fc0">【说唱】留住你一面，画在我心间</a> </p> <p><span class="s-fc4">by</span> <a title="JediMindTricks" href="/user/home?id=17647877" class="nm nm-icn f-thide s-fc3">JediMindTricks</a> <sup class="u-icn u-icn-84 "></sup> </p> </li>
<li>
<div class="u-cover u-cover-1">
<img class="j-flag" src="http://p1.music.126.net/If644P7ZrfPm_qcvtYyfzg==/18936888765458653.jpg?param=140y140" />
<a title="鞋子好看｜国产自赏摇滚噪音流行" href="/playlist?id=721462105" class="msk"></a>
<div class="bottom">
<a class="icon-play f-fr" title="播放" href="javascript:;" data-res-type="13" data-res-id="721462105" data-res-action="play"></a>
<span class="icon-headset"></span>
<span class="nb">77652</span>
</div>
</div> <p class="dec"> <a title="鞋子好看｜国产自赏摇滚噪音流行" href="/playlist?id=721462105" class="tit f-thide s-fc0">鞋子好看｜国产自赏摇滚噪音流行</a> </p> <p><span class="s-fc4">by</span> <a title="原创君" href="/user/home?id=201586" class="nm nm-icn f-thide s-fc3">原创君</a> <sup class="u-icn u-icn-1 "></sup> </p> </li>
</ul>
开始解析html源码
首先实例化一个BeautifulSoup对象，指定解析器为html.parser,通过BeautifulSoup对象的CSS选择器select_one()，这里用ID选择器搜索到无序列表ul，再通过find_all获取ul下的所有li标签，接着遍历li，获取到歌单的图片链接，歌单列表链接和歌单名称。
from bs4 import BeautifulSoup html = '''上面提取的html源码'''
soup = BeautifulSoup(html, 'html.parser')
ul = soup.select_one('#m-pl-container')
for li in ul.find_all('li'):
img_url = li.img['src']
a_msk = li.find('a', class_='msk')
musicList_url = 'http:/%s' % a_msk['href']
musicList_name = a_msk['title']
print(img_url,musicList_url,musicList_name) # 打印 http://p1.music.126.net/FGe-rVrHlBTbnOvhMR99PQ==/109951162989189558.jpg?param=140y140 http://playlist?id=832790627 【说唱】留住你一面，画在我心间
三、Beautiful Soup 4.4.0
Beautiful Soup 是一个可以从HTML或XML文件中提取数据的Python库.详细使用请转移官网 http://beautifulsoup.readthedocs.io/zh_CN/v4.4.0/