BeautifulSoup详解

BeautifulSoup

BeautifulSoup是一个模块，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。

举个简单的例子对其进行运用

from django.test import TestCase
 
# Create your tests here.
 
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')
 
# 循环所有标签
from bs4.element import Tag
from bs4.element import NavigableString
for tag in soup.body.descendants:
    if isinstance(tag,Tag):
        # print(tag.name,tag.attrs)
        pass
 
# 内容
# tag1 = soup.find(name='a')
# tag1.clear()
# print(soup)
 
# 属性
tag1 = soup.find(name='a')
del tag1.attrs['class']
print(soup)

常用参数介绍　　

name，标签名称

1 tag = soup.find('a')
2 name = tag.name # 获取该标签的名字
3 print(name)
4 tag.name = 'span' # 设置
5 print(soup)

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attr，标签属性

1 tag = soup.find('a')
2 attrs = tag.attrs # 获取
3 print(attrs)
4 tag.attrs = {'k':1}
5 tag.attrs['id'] = '22'
6 print(soup)

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children,所有子标签

1 body = soup.find('body')
2 v = body.children

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children,所有子子孙孙标签

1 body = soup.find('body')
2 v = body.descendants

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clear,将标签的所有子标签全部清空（保留标签名）

1 tag = soup.find('body')
2 tag.clear()
3 print(soup)

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decompose,递归的删除所有的标签

1 body = soup.find('body')
2 body.decompose()
3 print(soup)

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extract,递归的删除所有的标签，并获取删除的标签

1 body = soup.find('body')
2 v = body.extract()
3 print(soup)

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

1 body = soup.find('body')
2 v = body.decode()
3 v = body.decode_contents()
4 print(v)

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

1 body = soup.find('body')
2 v = body.encode()
3 v = body.encode_contents()
4 print(v)

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find,获取匹配的第一个标签

1 tag = soup.find('a')
2 print(tag)
3 tag = soup.find(name='a', attrs={'class': 'sister'}, recursive=True, text='Lacie')
4 tag = soup.find(name='a', class_='sister', recursive=True, text='Lacie')
5 print(tag)

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find_all,获取匹配的所有标签

 1 tags = soup.find_all('a')
 2 print(tags)
 3  
 4 tags = soup.find_all('a',limit=1)
 5 print(tags)
 6  
 7 tags = soup.find_all(name='a', attrs={'class': 'sister'}, recursive=True, text='Lacie')
 8 # tags = soup.find(name='a', class_='sister', recursive=True, text='Lacie')
 9 print(tags)
10 ####### 列表 #######
11 v = soup.find_all(name=['a','div'])
12 print(v)
13 v = soup.find_all(class_=['sister0', 'sister'])
14 print(v)
15 v = soup.find_all(text=['Tillie'])
16 print(v, type(v[0]))
17 v = soup.find_all(id=['link1','link2'])
18 print(v)
19 v = soup.find_all(href=['link1','link2'])
20 print(v)
21 ####### 正则 #######
22 importre
23 rep = re.compile('p')
24 rep = re.compile('^p')
25 v = soup.find_all(name=rep)
26 print(v)
27 rep = re.compile('sister.*')
28 v = soup.find_all(class_=rep)
29 print(v)
30 rep = re.compile('http://www.oldboy.com/static/.*')
31 v = soup.find_all(href=rep)
32 print(v)
33 ####### 方法筛选 #######
34 def func(tag):
35 return tag.has_attr('class') and tag.has_attr('id')
36 v = soup.find_all(name=func)
37 print(v)
38 ## get,获取标签属性
39 tag = soup.find('a')
40 v = tag.get('id')
41 print(v)

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has_attr,检查标签是否具有该属性

1 tag = soup.find('a')
2 v = tag.has_attr('id')
3 print(v)

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get_text,获取标签内部文本内容

1 tag = soup.find('a')
2 v = tag.get_text('id')
3 print(v)

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index,检查标签在某标签中的索引位置

1 tag = soup.find('body')
2 v = tag.index(tag.find('div'))
3 print(v)
4 tag = soup.find('body')
5 for i,v in enumerate(tag):
6 print(i,v)

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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'

1 tag = soup.find('br')
2 v = tag.is_empty_element
3 print(v)

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当前的关联标签

 1 # soup.next
 2 # soup.next_element
 3 # soup.next_elements
 4 # soup.next_sibling
 5 # soup.next_siblings
 6  
 7 #
 8 # tag.previous
 9 # tag.previous_element
10 # tag.previous_elements
11 # tag.previous_sibling
12 # tag.previous_siblings
13  
14 #
15 # tag.parent
16 # tag.parents

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查找某标签的关联标签

 1 # tag.find_next(...)
 2 # tag.find_all_next(...)
 3 # tag.find_next_sibling(...)
 4 # tag.find_next_siblings(...)
 5  
 6 # tag.find_previous(...)
 7 # tag.find_all_previous(...)
 8 # tag.find_previous_sibling(...)
 9 # tag.find_previous_siblings(...)
10  
11 # tag.find_parent(...)
12 # tag.find_parents(...)
13  
14 # 参数同find_all

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select,select_one, CSS选择器

 1 soup.select("title")
 2  
 3 soup.select("p nth-of-type(3)")
 4  
 5 soup.select("body a")
 6  
 7 soup.select("html head title")
 8  
 9 tag = soup.select("span,a")
10  
11 soup.select("head > title")
12  
13 soup.select("p > a")
14  
15 soup.select("p > a:nth-of-type(2)")
16  
17 soup.select("p > #link1")
18  
19 soup.select("body > a")
20  
21 soup.select("#link1 ~ .sister")
22  
23 soup.select("#link1 + .sister")
24  
25 soup.select(".sister")
26  
27 soup.select("[class~=sister]")
28  
29 soup.select("#link1")
30  
31 soup.select("a#link2")
32  
33 soup.select('a[href]')
34  
35 soup.select('a[href="http://example.com/elsie"]')
36  
37 soup.select('a[href^="http://example.com/"]')
38  
39 soup.select('a[href$="tillie"]')
40  
41 soup.select('a[href*=".com/el"]')
42  
43  
44 from bs4.element import Tag
45  
46 def default_candidate_generator(tag):
47     for child in tag.descendants:
48         if not isinstance(child, Tag):
49             continue
50         if not child.has_attr('href'):
51             continue
52         yield child
53  
54 tags = soup.find('body').select("a", _candidate_generator=default_candidate_generator)
55 print(type(tags), tags)
56  
57 from bs4.element import Tag
58 def default_candidate_generator(tag):
59     for child in tag.descendants:
60         if not isinstance(child, Tag):
61             continue
62         if not child.has_attr('href'):
63             continue
64         yield child
65  
66 tags = soup.find('body').select("a", _candidate_generator=default_candidate_generator, limit=1)
67 print(type(tags), tags)

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标签的内容

 1 # tag = soup.find('span')
 2 # print(tag.string)          # 获取
 3 # tag.string = 'new content' # 设置
 4 # print(soup)
 5  
 6 # tag = soup.find('body')
 7 # print(tag.string)
 8 # tag.string = 'xxx'
 9 # print(soup)
10  
11 # tag = soup.find('body')
12 # v = tag.stripped_strings  # 递归内部获取所有标签的文本
13 # print(v)

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append在当前标签内部追加一个标签

 1 # tag = soup.find('body')
 2 # tag.append(soup.find('a'))
 3 # print(soup)
 4 #
 5 # from bs4.element import Tag
 6 # obj = Tag(name='i',attrs={'id': 'it'})
 7 # obj.string = '我是一个新来的'
 8 # tag = soup.find('body')
 9 # tag.append(obj)
10 # print(soup)

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insert在当前标签内部指定位置插入一个标签

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

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

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

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replace_with 在当前标签替换为指定标签

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

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创建标签之间的关系

1 tag = soup.find('div')
2 a = soup.find('a')
3 tag.setup(previous_sibling=a)
4 print(tag.previous_sibling)

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wrap，将指定标签把当前标签包裹起来

 1 # from bs4.element import Tag
 2 # obj1 = Tag(name='div', attrs={'id': 'it'})
 3 # obj1.string = '我是一个新来的'
 4 #
 5 # tag = soup.find('a')
 6 # v = tag.wrap(obj1)
 7 # print(soup)
 8  
 9 # tag = soup.find('a')
10 # v = tag.wrap(soup.find('p'))
11 # print(soup)

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unwrap，去掉当前标签，将保留其包裹的标签

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更多详情见官方网站：http://beautifulsoup.readthedocs.io/zh_CN/v4.4.0/

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原文地址：https://www.cnblogs.com/hzpythoner/p/7169118.html