BeautifulSoup詳解

時間 2019-12-08

標籤 beautifulsoup 詳解简体版

原文原文鏈接

BeautifulSoup

BeautifulSoup是一個模塊，該模塊用於接收一個HTML或XML字符串，而後將其進行格式化，以後遍能夠使用他提供的方法進行快速查找指定元素，從而使得在HTML或XML中查找指定元素變得簡單。html

舉個簡單的例子對其進行運用python

 
           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總共</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" 
           ) 
          
           # 找到第一個a標籤 
          
           # tag1 = soup.find(name='a') 
          
           # 循環全部標籤 
          
           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 
          
           # 內容 
          
           # tag1 = soup.find(name='a') 
          
           # tag1.clear() 
          
           # print(soup) 
          
           # 屬性 
          
           tag1  
           =  
           soup.find(name 
           = 
           'a' 
           ) 
          
           del  
           tag1.attrs[ 
           'class' 
           ] 
          
           print 
           (soup)

經常使用參數介紹　　

name，標籤名稱django

1 tag = soup.find('a')
2 name = tag.name # 獲取該標籤的名字
3 print(name)
4 tag.name = 'span' # 設置
5 print(soup)

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attr，標籤屬性app

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

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children,全部子標籤ide

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

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children,全部子子孫孫標籤post

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

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clear,將標籤的全部子標籤所有清空（保留標籤名）網站

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

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decompose,遞歸的刪除全部的標籤spa

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

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extract,遞歸的刪除全部的標籤，並獲取刪除的標籤3d

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

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decode,轉換爲字符串（含當前標籤）；decode_contents（不含當前標籤）code

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

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encode,轉換爲字節（含當前標籤）；encode_contents（不含當前標籤）

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

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find,獲取匹配的第一個標籤

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,獲取匹配的全部標籤

 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 ####### 正則 #######
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 ####### 方法篩選 #######
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,獲取標籤屬性
39 tag = soup.find('a')
40 v = tag.get('id')
41 print(v)

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has_attr,檢查標籤是否具備該屬性

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

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get_text,獲取標籤內部文本內容

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

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index,檢查標籤在某標籤中的索引位置

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,是不是空標籤(是否能夠是空)或者自閉合標籤，

判斷是不是以下標籤：'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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當前的關聯標籤

 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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查找某標籤的關聯標籤

 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 # 參數同find_all

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select,select_one, CSS選擇器

 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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標籤的內容

 1 # tag = soup.find('span')
 2 # print(tag.string)          # 獲取
 3 # tag.string = 'new content' # 設置
 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  # 遞歸內部獲取全部標籤的文本
13 # print(v)

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append在當前標籤內部追加一個標籤

 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 = '我是一個新來的'
 8 # tag = soup.find('body')
 9 # tag.append(obj)
10 # print(soup)

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insert在當前標籤內部指定位置插入一個標籤

1 from bs4.element import Tag
2 obj = Tag(name='i', attrs={'id': 'it'})
3 obj.string = '我是一個新來的'
4 tag = soup.find('body')
5 tag.insert(2, obj)
6 print(soup)

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insert_after,insert_before 在當前標籤後面或前面插入

1 # from bs4.element import Tag
2 # obj = Tag(name='i', attrs={'id': 'it'})
3 # obj.string = '我是一個新來的'
4 # tag = soup.find('body')
5 # # tag.insert_before(obj)
6 # tag.insert_after(obj)
7 # print(soup)

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replace_with 在當前標籤替換爲指定標籤

1 from bs4.element import Tag
2 obj = Tag(name='i', attrs={'id': 'it'})
3 obj.string = '我是一個新來的'
4 tag = soup.find('div')
5 tag.replace_with(obj)
6 print(soup)

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建立標籤之間的關係

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，將指定標籤把當前標籤包裹起來

 1 # from bs4.element import Tag
 2 # obj1 = Tag(name='div', attrs={'id': 'it'})
 3 # obj1.string = '我是一個新來的'
 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，去掉當前標籤，將保留其包裹的標籤

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更多詳情見官方網站：http://beautifulsoup.readthedocs.io/zh_CN/v4.4.0/

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