zoukankan html css js c++ java

使用Beautiful Soup

Beautiful Soup初了解

# 解析工具Beautiful Soup，借助网页的结构和属性等特性来解析网页(简单的说就是python的一个HTML或XML的解析库)
# Beautiful Soup支持的解析器

解析器	使用方法	优势	劣势
Python标准库	BeautifulSoup(markup, " html. parser ")	Python 的内宜标准库、执行速度适中、文档容错能力强	Python 2.7.3及 Python3.2.2 之前的版本文档容错能力差
lxml HTML解析器	BeautifulSoup(markup,"lxml")	速度快、文档容错能力强	需要安装c语言库
lxmlXML解析器	BeautifulSoup(markup,"xml")	速度快、唯一支持 XML 的解析器	需要安装c语言库
html5lib	BeautifulSoup(markup,"htmlSlib")	最好的容错性、以浏览器的方式解析文梢、生成 HTML5 格式的文档	速度慢、不依赖外部扩展

实例引入：

1 from bs4 import BeautifulSoup
2 
3 soup = BeautifulSoup('<p>Hello</p>', 'lxml')
4 print(soup.p.string)
5 
6 
7 # 输出：
8 Hello

View Code

Beautiful Soup基本用法

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <html><head><title>The Dormouse's story</title></head>
 5 <body>
 6 <p class="title" name="dromouse"><b>The Dormouse's story</b></p>
 7 <p class="story">Once upon a time there were three little sisters; and their names were
 8 <a href="http://example.com/elsie" class="sister" id="link1"><!-- Elsie --></a>,
 9 <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
10 <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
11 and they lived at the bottom of a well.</p>
12 <p class="story">...</p>
13 """
14 
15 soup = BeautifulSoup(html, 'lxml')
16 print(soup.prettify(), soup.title.string, sep='

')
17 # 初始化BeautifulSoup时，自动更正了不标准的HTML
18 # prettify()方法可以把要解析的字符串以标准的缩进格式输出
19 # soup.title 可以选出HTML中的title节点，再调用string属性就可以得到里面的文本了
20 
21 
22 # 输出：
23 <html>
24  <head>
25   <title>
26    The Dormouse's story
27   </title>
28  </head>
29  <body>
30   <p class="title" name="dromouse">
31    <b>
32     The Dormouse's story
33    </b>
34   </p>
35   <p class="story">
36    Once upon a time there were three little sisters; and their names were
37    <a class="sister" href="http://example.com/elsie" id="link1">
38     <!-- Elsie -->
39    </a>
40    ,
41    <a class="sister" href="http://example.com/lacie" id="link2">
42     Lacie
43    </a>
44    and
45    <a class="sister" href="http://example.com/tillie" id="link3">
46     Tillie
47    </a>
48    ;
49 and they lived at the bottom of a well.
50   </p>
51   <p class="story">
52    ...
53   </p>
54  </body>
55 </html>
56 
57 The Dormouse's story

View Code

节点选择器

# 选择元素

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <html><head><title>The Dormouse's story</title></head>
 5 <body>
 6 <p class="title" name="dromouse"><b>The Dormouse's story</b></p>
 7 <p class="story">Once upon a time there were three little sisters; and their names were
 8 <a href="http://example.com/elsie" class="sister" id="link1"><!-- Elsie --></a>,
 9 <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
10 <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
11 and they lived at the bottom of a well.</p>
12 <p class="story">...</p>
13 """
14 
15 soup = BeautifulSoup(html, 'lxml')
16 
17 print(soup.title)               # 打印输出title节点的选择结果
18 print(type(soup.title))         # 输出soup.title类型
19 print(soup.title.string)        # 输出title节点的内容
20 print(soup.head)                # 打印输出head节点的选择结果
21 print(soup.p)                   # 打印输出p节点的选择结果
22 
23 
24 # 输出：
25 <title>The Dormouse's story</title>
26 <class 'bs4.element.Tag'>
27 The Dormouse's story
28 <head><title>The Dormouse's story</title></head>
29 <p class="title" name="dromouse"><b>The Dormouse's story</b></p>

View Code

# 提取信息
    # 调用string属性获取文本的值
    # 利用那么属性获取节点的名称
    # 调用attrs获取所有HTML节点属性

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <html><head><title>The Dormouse's story</title></head>
 5 <body>
 6 <p class="title" name="dromouse"><b>The Dormouse's story</b></p>
 7 <p class="story">Once upon a time there were three little sisters; and their names were
 8 <a href="http://example.com/elsie" class="sister" id="link1"><!-- Elsie --></a>,
 9 <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
10 <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
11 and they lived at the bottom of a well.</p>
12 <p class="story">...</p>
13 """
14 
15 soup = BeautifulSoup(html, 'lxml')
16 
17 print(soup.title.name)          # 选取title节点，然后调用name属性获得节点名称
18 # 输出：title
19 print(soup.title.string)        # 调用string属性，获取title节点的文本值
20 # 输出：The Dormouse's story
21 
22 print(soup.p.attrs)             # 调用attrs，获取p节点的所有属性
23 # 输出：{'class': ['title'], 'name': 'dromouse'}
24 
25 print(soup.p.attrs['name'])         # 获取name属性
26 # 输出：dromouse
27 print(soup.p['name'])               # 获取name属性
28 # 输出：dromouse

View Code

# 嵌套选择

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <html><head><title>The Dormouse's story</title></head>
 5 <body>
 6 """
 7 
 8 soup = BeautifulSoup(html, 'lxml')
 9 print(soup.head.title)
10 print(type(soup.head.title))
11 print(soup.head.title.string)
12 
13 # 输出：
14 <title>The Dormouse's story</title>
15 <class 'bs4.element.Tag'>
16 The Dormouse's story

View Code

# 关联选择
    # 1、子节点和子孙节点
        # contents属性得到的结果是直接子节点的列表。

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <html>
 5  <head>
 6   <title>
 7    The Dormouse's story
 8   </title>
 9  </head>
10  <body>
11   <p class="story">
12    Once upon a time there were three little sisters; and their names were
13    <a class="sister" href="http://example.com/elsie" id="link1">
14     <!-- Elsie -->
15    </a>
16    ,
17    <a class="sister" href="http://example.com/lacie" id="link2">
18     Lacie
19    </a>
20    and
21    <a class="sister" href="http://example.com/tillie" id="link3">
22     Tillie
23    </a>
24    ;
25 and they lived at the bottom of a well.
26   </p>
27   <p class="story">
28    ...
29   </p>
30  </body>
31 </html>
32 """
33 
34 soup = BeautifulSoup(html, 'lxml')
35 # 选取节点元素之后，可以调用contents属性获取它的直接子节点
36 print(soup.p.contents)
37 
38 # 输出：
39 ['
   Once upon a time there were three little sisters; and their names were
   ', <a class="sister" href="http://example.com/elsie" id="link1">
40 <!-- Elsie -->
41 </a>, '
   ,
   ', <a class="sister" href="http://example.com/lacie" id="link2">
42     Lacie
43    </a>, '
   and
   ', <a class="sister" href="http://example.com/tillie" id="link3">
44     Tillie
45    </a>, '
   ;
and they lived at the bottom of a well.
  ']
46 # 返回结果是一个列表，列表中的元素是所选节点的直接子节点（不包括孙节点）

直接子节点

        # children属性，返回结果是生成器类型。与contents属性一样，只是返回结果类型不同。

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <html>
 5  <head>
 6   <title>
 7    The Dormouse's story
 8   </title>
 9  </head>
10  <body>
11   <p class="story">
12    Once upon a time there were three little sisters; and their names were
13    <a class="sister" href="http://example.com/elsie" id="link1">
14     <span>Elsie</span>
15    </a>
16    ,
17    <a class="sister" href="http://example.com/lacie" id="link2">
18     Lacie
19    </a>
20    and
21    <a class="sister" href="http://example.com/tillie" id="link3">
22     Tillie
23    </a>
24    ;
25 and they lived at the bottom of a well.
26   </p>
27   <p class="story">
28    ...
29   </p>
30  </body>
31 </html>
32 """
33 
34 soup = BeautifulSoup(html, 'lxml')
35 print(soup.p.children)                          # 输出：<list_iterator object at 0x1159b7668>
36 for i, child in enumerate(soup.p.children):
37     print(i, child)
38 
39 
40 # for 循环的输出结果:
41 0 
42    Once upon a time there were three little sisters; and their names were
43    
44 1 <a class="sister" href="http://example.com/elsie" id="link1">
45 <span>Elsie</span>
46 </a>
47 2 
48    ,
49    
50 3 <a class="sister" href="http://example.com/lacie" id="link2">
51     Lacie
52    </a>
53 4 
54    and
55    
56 5 <a class="sister" href="http://example.com/tillie" id="link3">
57     Tillie
58    </a>
59 6 
60    ;
61 and they lived at the bottom of a well.
62

直接子节点

        # descendants属性会递归查询所有子节点，得到所有子孙节点。

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <html>
 5  <head>
 6   <title>
 7    The Dormouse's story
 8   </title>
 9  </head>
10  <body>
11   <p class="story">
12    Once upon a time there were three little sisters; and their names were
13    <a class="sister" href="http://example.com/elsie" id="link1">
14     <span>Elsie</span>
15    </a>
16    ,
17    <a class="sister" href="http://example.com/lacie" id="link2">
18     Lacie
19    </a>
20    and
21    <a class="sister" href="http://example.com/tillie" id="link3">
22     Tillie
23    </a>
24    ;
25 and they lived at the bottom of a well.
26   </p>
27   <p class="story">
28    ...
29   </p>
30  </body>
31 </html>
32 """
33 
34 soup = BeautifulSoup(html, 'lxml')
35 print(soup.p.descendants)                          # 输出：<generator object Tag.descendants at 0x1131d0048>
36 for i, child in enumerate(soup.p.descendants):
37     print(i, child)
38 
39 
40 
41 # for 循环输出结果：
42 0 
43    Once upon a time there were three little sisters; and their names were
44    
45 1 <a class="sister" href="http://example.com/elsie" id="link1">
46 <span>Elsie</span>
47 </a>
48 2 
49 
50 3 <span>Elsie</span>
51 4 Elsie
52 5 
53 
54 6 
55    ,
56    
57 7 <a class="sister" href="http://example.com/lacie" id="link2">
58     Lacie
59    </a>
60 8 
61     Lacie
62    
63 9 
64    and
65    
66 10 <a class="sister" href="http://example.com/tillie" id="link3">
67     Tillie
68    </a>
69 11 
70     Tillie
71    
72 12 
73    ;
74 and they lived at the bottom of a well.
75

获取子孙节点

    # 2、父节点和祖先节点

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <html>
 5  <head>
 6   <title>
 7    The Dormouse's story
 8   </title>
 9  </head>
10  <body>
11   <p class="story">
12    Once upon a time there were three little sisters; and their names were
13    <a class="sister" href="http://example.com/elsie" id="link1">
14     <span>Elsie</span>
15    </a>
16   </p>
17   <p class="story">
18    ...
19   </p>
20  </body>
21 </html>
22 """
23 
24 soup = BeautifulSoup(html, 'lxml')
25 print(soup.a.parent)
26 
27 
28 # 输出：
29 <p class="story">
30    Once upon a time there were three little sisters; and their names were
31    <a class="sister" href="http://example.com/elsie" id="link1">
32 <span>Elsie</span>
33 </a>
34 </p>

parent获取某个节点的一个父节点

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <html>
 5  <head>
 6   <title>
 7    The Dormouse's story
 8   </title>
 9  </head>
10  <body>
11   <p class="story">
12    Once upon a time there were three little sisters; and their names were
13    <a class="sister" href="http://example.com/elsie" id="link1">
14     <span>Elsie</span>
15    </a>
16   </p>
17   <p class="story">
18    ...
19   </p>
20  </body>
21 </html>
22 """
23 
24 soup = BeautifulSoup(html, 'lxml')
25 print(soup.a.parents, type(soup.a.parents), list(enumerate(soup.a.parents)), sep='

')
26 
27 
28 # 输出：
29 <generator object PageElement.parents at 0x11c76e048>
30 
31 <class 'generator'>
32 
33 [(0, <p class="story">
34    Once upon a time there were three little sisters; and their names were
35    <a class="sister" href="http://example.com/elsie" id="link1">
36 <span>Elsie</span>
37 </a>
38 </p>), (1, <body>
39 <p class="story">
40    Once upon a time there were three little sisters; and their names were
41    <a class="sister" href="http://example.com/elsie" id="link1">
42 <span>Elsie</span>
43 </a>
44 </p>
45 <p class="story">
46    ...
47   </p>
48 </body>), (2, <html>
49 <head>
50 <title>
51    The Dormouse's story
52   </title>
53 </head>
54 <body>
55 <p class="story">
56    Once upon a time there were three little sisters; and their names were
57    <a class="sister" href="http://example.com/elsie" id="link1">
58 <span>Elsie</span>
59 </a>
60 </p>
61 <p class="story">
62    ...
63   </p>
64 </body>
65 </html>), (3, <html>
66 <head>
67 <title>
68    The Dormouse's story
69   </title>
70 </head>
71 <body>
72 <p class="story">
73    Once upon a time there were three little sisters; and their names were
74    <a class="sister" href="http://example.com/elsie" id="link1">
75 <span>Elsie</span>
76 </a>
77 </p>
78 <p class="story">
79    ...
80   </p>
81 </body>
82 </html>
83 )]

parent获取所有祖先节点

        # 涉及内置函数enumerate()
        # enumerate() 函数用于将一个可遍历的数据对象(如列表、元组或字符串)组合为一个索引序列，同时列出数据和数据下标，一般用在 for 循环当中。

 1 # enumerate() 函数用于将一个可遍历的数据对象(如列表、元组或字符串)组合为一个索引序列，同时列出数据和数据下标，一般用在 for 循环当中。
 2 
 3 a = ["恕", "我", "直", "言", "在", "坐", "的", "各", "位", "都", "是", "爱", "学", "习", "的"]
 4 print(a)            # 输出：['恕', '我', '直', '言', '在', '坐', '的', '各', '位', '都', '是', '爱', '学', '习', '的']
 5 b = enumerate(a)
 6 print(enumerate(a))     # 输出：<enumerate object at 0x11a1f8b40>
 7 print(list(b))
 8 # [(0, '恕'), (1, '我'), (2, '直'), (3, '言'), (4, '在'), (5, '坐'), (6, '的'), (7, '各'), (8, '位'), (9, '都'),
 9 # (10, '是'), (11, '爱'), (12, '学'), (13, '习'), (14, '的')]
10 
11 for m, n in enumerate(a):
12     print(m, n)
13 # for 循环 输出：
14 0 恕
15 1 我
16 2 直
17 3 言
18 4 在
19 5 坐
20 6 的
21 7 各
22 8 位
23 9 都
24 10 是
25 11 爱
26 12 学
27 13 习
28 14 的

enumerate()内置函数

    # 3、兄弟节点

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <html>
 5  <head>
 6   <title>
 7    The Dormouse's story
 8   </title>
 9  </head>
10  <body>
11   <p class="story">
12    Once upon a time there were three little sisters; and their names were
13    <a class="sister" href="http://example.com/elsie" id="link1">
14     <span>Elsie</span>
15    </a>
16    ,
17    <a class="sister" href="http://example.com/lacie" id="link2">
18     Lacie
19    </a>
20    and
21    <a class="sister" href="http://example.com/tillie" id="link3">
22     Tillie
23    </a>
24    ;
25 and they lived at the bottom of a well.
26   </p>
27   <p class="story">
28    ...
29   </p>
30  </body>
31 </html>
32 """
33 
34 soup = BeautifulSoup(html, 'lxml')
35 print(
36     # 获取下一个兄弟元素
37     {'Next Sibling': soup.a.next_sibling},
38     # 获取上一个兄弟元素
39     {'Previous Sibling': soup.a.previous_sibling},
40     # 返回后面的兄弟元素
41     {'Next Siblings': list(enumerate(soup.a.next_siblings))},
42     # 返回前面的兄弟元素
43     {'Previous Siblings': list(enumerate(soup.a.previous_siblings))},
44 
45     sep='

'
46 )
47 
48 
49 # 输出：
50 {'Next Sibling': '
   ,
   '}
51 
52 {'Previous Sibling': '
   Once upon a time there were three little sisters; and their names were
   '}
53 
54 {'Next Siblings': [(0, '
   ,
   '), (1, <a class="sister" href="http://example.com/lacie" id="link2">
55     Lacie
56    </a>), (2, '
   and
   '), (3, <a class="sister" href="http://example.com/tillie" id="link3">
57     Tillie
58    </a>), (4, '
   ;
and they lived at the bottom of a well.
  ')]}
59 
60 {'Previous Siblings': [(0, '
   Once upon a time there were three little sisters; and their names were
   ')]}

获取同级节点

    # 4、提取信息

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <html>
 5  <body>
 6   <p class="story">
 7    Once upon a time there were three little sisters; and their names were
 8    <a class="sister" href="http://example.com/elsie" id="link1">Bob</a>
 9    <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>
10   </p>
11  </body>
12 </html>
13 """
14 
15 soup = BeautifulSoup(html, 'lxml')
16 print(
17     'Next Sibling:',
18 
19     [soup.a.next_sibling],        # 获取上一个兄弟节点
20     # 

21     type(soup.a.next_sibling),      # 上一个兄弟节点的类型
22     # <class 'bs4.element.NavigableString'>
23     [soup.a.next_sibling.string],     # 获取上一个兄弟节点的内容
24     # 

25     sep='
'
26 )
27 
28 print(
29     'Parent:',
30 
31     [type(soup.a.parents)],      # 获取所有的祖先节点
32     # <class 'generator'>
33     [list(soup.a.parents)[0]],           # 获取第一个祖先节点
34     # <p class="story">
35    Once upon a time there were three little sisters; and their names were
36    <a class="sister" href="http://example.com/elsie" id="link1">Bob</a>
37 <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>
38 </p>
39     [list(soup.a.parents)[0].attrs['class']],        # 获取第一个祖先节点的"class属性"的值
40     # ['story']
41     sep='
'
42 )
43 
44 # 为了输出返回的结果，均以列表形式
45 
46 
47 # 输出：
48 Next Sibling:
49 ['
']
50 <class 'bs4.element.NavigableString'>
51 ['
']
52 Parent:
53 [<class 'generator'>]
54 [<p class="story">
55    Once upon a time there were three little sisters; and their names were
56    <a class="sister" href="http://example.com/elsie" id="link1">Bob</a>
57 <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>
58 </p>]
59 [['story']]

View Code

方法选择器

find_all(name=None, attrs={}, recursive=True, text=None, limit=None, **kwargs)
# 查询所有符合条件的元素

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <div>
 5 <ul>
 6 <li class="item-O"><a href="linkl.html">first item</a></li>
 7 <li class="item-1"><a href="link2.html">second item</a></li>
 8 <li class="item-inactive"><a href="link3.html">third item</a></li>
 9 <li class="item-1"><a href="link4.html">fourth item</a></li>
10 <li class="item-0"><a href="link5.html">fifth item</a>
11 </ul>
12 </div>
13 """
14 
15 soup = BeautifulSoup(html, 'lxml')
16 print(soup.find_all(name='li'),
17       type(soup.find_all(name='li')[0]),
18       sep='

')
19 
20 
21 # 输出：
22 [<li class="item-O"><a href="linkl.html">first item</a></li>, <li class="item-1"><a href="link2.html">second item</a></li>, <li class="item-inactive"><a href="link3.html">third item</a></li>, <li class="item-1"><a href="link4.html">fourth item</a></li>, <li class="item-0"><a href="link5.html">fifth item</a>
23 </li>]
24 
25 <class 'bs4.element.Tag'>
26 
27 
28 # 返回值是一个列表，列表的元素是名为"li"的节点，每个元素都是bs4.element.Tag类型
29 
30 
31 # 遍历每个a节点
32 from bs4 import BeautifulSoup
33 
34 html = """
35 <div>
36 <ul>
37 <li class="item-O"><a href="linkl.html">first item</a></li>
38 <li class="item-1"><a href="link2.html">second item</a></li>
39 <li class="item-inactive"><a href="link3.html">third item</a></li>
40 <li class="item-1"><a href="link4.html">fourth item</a></li>
41 <li class="item-0"><a href="link5.html">fifth item</a>
42 </ul>
43 </div>
44 """
45 
46 soup = BeautifulSoup(html, 'lxml')
47 li = soup.find_all(name='li')
48 
49 for a in li:
50     print(a.find_all(name='a'))
51 
52 # 输出：
53 [<a href="linkl.html">first item</a>]
54 [<a href="link2.html">second item</a>]
55 [<a href="link3.html">third item</a>]
56 [<a href="link4.html">fourth item</a>]
57 [<a href="link5.html">fifth item</a>]

name参数

 1 from bs4 import BeautifulSoup
 2 
 3 html = """
 4 <div>
 5 <ul>
 6 <li class="item-O"><a href="linkl.html">first item</a></li>
 7 <li class="item-1"><a href="link2.html">second item</a></li>
 8 <li class="item-inactive"><a href="link3.html">third item</a></li>
 9 <li class="item-1"><a href="link4.html">fourth item</a></li>
10 <li class="item-0"><a href="link5.html">fifth item</a>
11 </ul>
12 </div>
13 """
14 
15 soup = BeautifulSoup(html, 'lxml')
16 
17 print(soup.find_all(attrs={'class': 'item-0'}))
18 print(soup.find_all(attrs={'href': 'link5.html'}))
19 
20 
21 # 输出：
22 [<li class="item-0"><a href="link5.html">fifth item</a>
23 </li>]
24 [<a href="link5.html">fifth item</a>]
25 
26 # 可以通过attrs参数传入一些属性来进行查询，即通过特定的属性来查询
27 # find_all(attrs={'属性名': '属性值', ......})

attrs参数

 1 from bs4 import BeautifulSoup
 2 import re
 3 
 4 html = """
 5 <div class="panel">
 6 <div class="panel-body">
 7 <a>Hello, this is a link</a>
 8 <a>Hello, this is a link, too</a>
 9 <div/>
10 <div/>
11 """
12 
13 soup = BeautifulSoup(html, 'lxml')
14 
15 # 正则表达式规则对象
16 regular = re.compile('link')
17 
18 # text参数课用来匹配节点的文本，传入的形式可以是字符串，也可以是正则表达式对象
19 print(soup.find_all(text=regular))
20 
21 # 正则匹配输出
22 print(re.findall(regular, html))
23 
24 
25 # 输出：
26 ['Hello, this is a link', 'Hello, this is a link, too']
27 ['link', 'link']

text参数

find(name=None, attrs={}, recursive=True, text=None, **kwargs)

仅返回与给定条件匹配标记的第一个元素

CSS选择器

Beautiful Soup 提供了CSS选择器，调用select()方法即可
css选择器用法：http://www.w3school.com.cn/cssref/css_selectors.asp

select(selector, namespaces=None, limit=None, **kwargs)

 1 html = '''
 2 <div class="panel">
 3 <div class="panel-heading">
 4 <h4>Hello</h4>
 5 </div>
 6 <div class="panel-body">
 7 <ul class="list" id="list-1">
 8 <li class="element">Foo</li>
 9 <li class="element">Bar</li>
10 <li class="element">Jay</li>
11 </ul>
12 <ul class="list list-small" id="list-2">
13 <li class="element">Foo</li>
14 <li class="element">Bar</li>
15 </ul>
16 </div>
17 </div>
18 '''
19 
20 from bs4 import BeautifulSoup
21 soup = BeautifulSoup(html, 'lxml')
22 
23 print(
24     soup.select('.panel .panel-heading'),
25 
26     soup.select('ul li'),
27 
28     soup.select('#list-2 .element'),
29 
30     type(soup.select('ul')[0]),
31 
32     sep='

'
33 )
34 
35 
36 # 输出：
37 [<div class="panel-heading">
38 <h4>Hello</h4>
39 </div>]
40 
41 [<li class="element">Foo</li>, <li class="element">Bar</li>, <li class="element">Jay</li>, <li class="element">Foo</li>, <li class="element">Bar</li>]
42 
43 [<li class="element">Foo</li>, <li class="element">Bar</li>]
44 
45 <class 'bs4.element.Tag'>

简单示例

 1 html = '''
 2 <div class="panel">
 3 <div class="panel-heading">
 4 <h4>Hello</h4>
 5 </div>
 6 <div class="panel-body">
 7 <ul class="list" id="list-1">
 8 <li class="element">Foo</li>
 9 <li class="element">Bar</li>
10 <li class="element">Jay</li>
11 </ul>
12 <ul class="list list-small" id="list-2">
13 <li class="element">Foo</li>
14 <li class="element">Bar</li>
15 </ul>
16 </div>
17 </div>
18 '''
19 
20 from bs4 import BeautifulSoup
21 soup = BeautifulSoup(html, 'lxml')
22 
23 ul_all = soup.select('ul')
24 print(ul_all)
25 
26 for ul in ul_all:
27     print()
28     print(
29         ul['id'],
30 
31         ul.select('li'),
32 
33         sep='
'
34     )
35 
36 
37 # 输出：
38 [<ul class="list" id="list-1">
39 <li class="element">Foo</li>
40 <li class="element">Bar</li>
41 <li class="element">Jay</li>
42 </ul>, <ul class="list list-small" id="list-2">
43 <li class="element">Foo</li>
44 <li class="element">Bar</li>
45 </ul>]
46 
47 list-1
48 [<li class="element">Foo</li>, <li class="element">Bar</li>, <li class="element">Jay</li>]
49 
50 list-2
51 [<li class="element">Foo</li>, <li class="element">Bar</li>]

嵌套选择

 1 html = '''
 2 <div class="panel">
 3 <div class="panel-heading">
 4 <h4>Hello</h4>
 5 </div>
 6 <div class="panel-body">
 7 <ul class="list" id="list-1">
 8 <li class="element">Foo</li>
 9 <li class="element">Bar</li>
10 <li class="element">Jay</li>
11 </ul>
12 <ul class="list list-small" id="list-2">
13 <li class="element">Foo</li>
14 <li class="element">Bar</li>
15 </ul>
16 </div>
17 </div>
18 '''
19 
20 from bs4 import BeautifulSoup
21 soup = BeautifulSoup(html, 'lxml')
22 
23 ul_all = soup.select('ul')
24 print(ul_all)
25 
26 for ul in ul_all:
27     print()
28     print(
29         ul['id'],
30 
31         ul.attrs['id'],
32 
33         sep='
'
34     )
35 
36 # 直接传入中括号和属性名  或者  通过attrs属性获取属性值 都可以成功获得属性值
37 
38 # 输出：
39 [<ul class="list" id="list-1">
40 <li class="element">Foo</li>
41 <li class="element">Bar</li>
42 <li class="element">Jay</li>
43 </ul>, <ul class="list list-small" id="list-2">
44 <li class="element">Foo</li>
45 <li class="element">Bar</li>
46 </ul>]
47 
48 list-1
49 list-1
50 
51 list-2
52 list-2

获取属性

 1 html = '''
 2 <div class="panel">
 3 <div class="panel-heading">
 4 <h4>Hello</h4>
 5 </div>
 6 <div class="panel-body">
 7 <ul class="list" id="list-1">
 8 <li class="element">Foo</li>
 9 <li class="element">Bar</li>
10 <li class="element">Jay</li>
11 </ul>
12 <ul class="list list-small" id="list-2">
13 <li class="element">Foo</li>
14 <li class="element">Bar</li>
15 </ul>
16 </div>
17 </div>
18 '''
19 
20 from bs4 import BeautifulSoup
21 soup = BeautifulSoup(html, 'lxml')
22 
23 ul_all = soup.select('li')
24 print(ul_all)
25 
26 for li in ul_all:
27     print()
28     print(
29         'get_text()方法获取文本：'+li.get_text(),
30 
31         'string属性获取文本：'+li.string,
32 
33         sep='
'
34     )
35 
36 
37 # 输出：
38 [<li class="element">Foo</li>, <li class="element">Bar</li>, <li class="element">Jay</li>, <li class="element">Foo</li>, <li class="element">Bar</li>]
39 
40 get_text()方法获取文本：Foo
41 string属性获取文本：Foo
42 
43 get_text()方法获取文本：Bar
44 string属性获取文本：Bar
45 
46 get_text()方法获取文本：Jay
47 string属性获取文本：Jay
48 
49 get_text()方法获取文本：Foo
50 string属性获取文本：Foo
51 
52 get_text()方法获取文本：Bar
53 string属性获取文本：Bar

获取文本

查看全文

相关阅读:
Java内存泄漏分析系列之七：使用MAT的Histogram和Dominator Tree定位溢出源
 Java内存泄漏分析系列之六：JVM Heap Dump（堆转储文件）的生成和MAT的使用
 Java内存泄漏分析系列之五：常见的Thread Dump日志案例分析
 Java内存泄漏分析系列之四：jstack生成的Thread Dump日志线程状态
 Java内存泄漏分析系列之三：jstat命令的使用及VM Thread分析
 Java内存泄漏分析系列之二：jstack生成的Thread Dump日志结构解析
 Java内存泄漏分析系列之一：使用jstack定位线程堆栈信息
 安全框架Shiro
JDK动态代理与CGLib动态代理
 解读分库分表中间件Sharding-JDBC

原文地址：https://www.cnblogs.com/liyihua/p/11080170.html