一、BeautifulSoup的基本使用
1 from bs4 import BeautifulSoup
2 from bs4 import SoupStrainer
3 import re
4
5
6 html_doc = """
7 <html>
8 <head>
9 <title>
10 The Dormouse's story
11 </title>
12 </head>
13 <body>
14 <p class="title">
15 <b>
16 The Dormouse's story
17 </b>
18 </p>
19 <p class="story">
20 Once upon a time there were three little sisters; and their names were
21 <a class="sister" href="http://example.com/elsie" id="link1">
22 Elsie
23 </a>
24 ,
25 <a class="sister" href="http://example.com/lacie" id="link2">
26 Lacie
27 </a>
28 and
29 <a class="sister" href="http://example.com/tillie" id="link3">
30 Tillie
31 </a>
32 ; and they lived at the bottom of a well.
33 </p>
34 <p class="story">
35 ...
36 </p>
37 </body>
38 </html>
39 """
40 soup = BeautifulSoup(html_doc, "html.parser")
41 # print(soup.prettify()) # 打印所有标准化html code
42 print('-----------------------------')
43 print(soup.title)
44 print('----------------------------')
45 print(soup.title.name)
46 print('----------------------------')
47 print(soup.title.string)
48 print('----------------------------')
49 print(soup.title.parent.name)
50 print('----------------------------')
51 print(soup.p)
52 # item_b = soup.p.
53 print('----------------------------')
54 print(soup.p['class'])
55 print('----------------------------')
56 print(soup.find_all('a'))
57 print('----------------------------')
58 print(soup.find(id='link3'))
59 print(soup.find(id='link3')['class'])
60 print(soup.find(id='link3')['href']) # 打印指定属性文本
61 print(soup.find(id='link3')['id'])
62 print(soup.find(id='link3').get_text()) # 打印文本
63
64 # find_all(name, attrs, recursive, text, limit, **kwargs)
65 # name 参数
66 soup.find_all('title')
67
68 # keyword参数
69 soup.find_all(id='link2')
70 soup.find_all(href=re.compile("elsie"))
71 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
72 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
73 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:
74 soup.find_all('a', limit=2) # 当搜索结果到达limit个数，就停止搜索
75
76 # 按CSS搜索
77 soup.find_all("a", class_="sister")
78 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
79
80 # CSS选择器
81 title_list = soup.select('head > title') # 查找所有满足条件的元素
82 title_list_one = soup.select_one('head > title') # 查找单个满足条件的元素
83 print(title_list) # 打印 [<title> The Dormouse's story</title>]
84 print(title_list[0].string) # 打印The Dormouse's story<
85
86 # 文档中找到所有<a>标签的链接：
87 for link in soup.find_all('a'):
88 print(link.get('href'))
89 # http://example.com/elsie
90 # http://example.com/lacie
91 # http://example.com/tillie
92
93 # find查找元素第一个类样式未story的p标签
94 p_story = soup.find('p',class_='story')
95 # print(p_story.a)
96
97 # 使用正则表达式
98 p_re_all = soup.find_all(re.compile('p'))
99 print(p_re_all)
100
101 # find_all查找所有class_=True匹配任何类样式的p标签
102 p_all = soup.find_all('p', class_=True)
103 # print(p_all) # 打印数组
104 # [<p class="title">
105 # <b>
106 # The Dormouse's story
107 # </b>
108 # </p>, <p class="story">
109 # Once upon a time there were three little sisters; and their names were
110 # <a class="sister" href="http://example.com/elsie" id="link1">
111 # Elsie
112 # </a>
113 # ,
114 # <a class="sister" href="http://example.com/lacie" id="link2">
115 # Lacie
116 # </a>
117 # and
118 # <a class="sister" href="http://example.com/tillie" id="link3">
119 # Tillie
120 # </a>
121 # ; and they lived at the bottom of a well.
122 # </p>, <p class="story">
123 # ...
124 # </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
1 <ul class="m-cvrlst f-cb" id="m-pl-container">
2 <li>
3 <div class="u-cover u-cover-1">
4 <img class="j-flag" src="http://p1.music.126.net/FGe-rVrHlBTbnOvhMR99PQ==/109951162989189558.jpg?param=140y140" />
5 <a title="【说唱】留住你一面，画在我心间" href="/playlist?id=832790627" class="msk"></a>
6 <div class="bottom">
7 <a class="icon-play f-fr" title="播放" href="javascript:;" data-res-type="13" data-res-id="832790627" data-res-action="play"></a>
8 <span class="icon-headset"></span>
9 <span class="nb">1615</span>
10 </div>
11 </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>
12 <li>
13 <div class="u-cover u-cover-1">
14 <img class="j-flag" src="http://p1.music.126.net/If644P7ZrfPm_qcvtYyfzg==/18936888765458653.jpg?param=140y140" />
15 <a title="鞋子好看｜国产自赏摇滚噪音流行" href="/playlist?id=721462105" class="msk"></a>
16 <div class="bottom">
17 <a class="icon-play f-fr" title="播放" href="javascript:;" data-res-type="13" data-res-id="721462105" data-res-action="play"></a>
18 <span class="icon-headset"></span>
19 <span class="nb">77652</span>
20 </div>
21 </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>
22 </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。
1 from bs4 import BeautifulSoup
2
3 html = '''上面提取的html源码'''
4 soup = BeautifulSoup(html, 'html.parser')
5 ul = soup.select_one('#m-pl-container')
6 for li in ul.find_all('li'):
7 img_url = li.img['src']
8 a_msk = li.find('a', class_='msk')
9 musicList_url = 'http:/%s' % a_msk['href']
10 musicList_name = a_msk['title']
11 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/