使用Python爬虫库BeautifulSoup遍历文档树并对标签进行操作详解

 html_doc = """ 
The Dormouse's story
Once upon a time there were three little sisters; and their names were Elsie, Lacie and Tillie; and they lived at the bottom of a well.
...
 """ from bs4 import BeautifulSoup soup = BeautifulSoup(html_doc,'lxml')

 print(soup.head) print(soup.title)

 soup.find_all('a')

 [Elsie, Lacie, Tillie]

 head_tag = soup.head head_tag.contents

 []

 title_tag = head_tag.contents[0] title_tag

 title_tag.contents

 ["The Dormouse's story"]

 for child in title_tag.children: print(child)

 The Dormouse's story 

 for child in head_tag.children: print(child)

 for child in head_tag.descendants: print(child)

  The Dormouse's story

 title_tag.string

 "The Dormouse's story" 

 head_tag.string

 "The Dormouse's story" 

 print(soup.html.string)

 None

 for string in soup.strings: print(string)

 The Dormouse's story The Dormouse's story Once upon a time there were three little sisters; and their names were Elsie , Lacie and Tillie ; and they lived at the bottom of a well. ...

 for string in soup.stripped_strings: print(string)

 The Dormouse's story The Dormouse's story Once upon a time there were three little sisters; and their names were Elsie , Lacie and Tillie ; and they lived at the bottom of a well. ...

 title_tag = soup.title title_tag.parent

 title_tag.string.parent

 link = soup.a for parent in link.parents: if parent is None: print(parent) else: print(parent.name)

 p body html [document]

 sibling_soup = BeautifulSoup("text1text2",'lxml') print(sibling_soup.prettify())

     text1  text2 

 sibling_soup.b.next_sibling

 text2

 sibling_soup.c.previous_sibling

 text1

 soup.find_all('a')

 [Elsie, Lacie, Tillie]

 soup.a.next_sibling # 第一个的next_sibling是,\n

 ',\n' 

 soup.a.next_sibling.next_sibling

 Lacie

 for sibling in soup.a.next_siblings: print(repr(sibling))

 ',\n' Lacie ' and\n' Tillie ';\nand they lived at the bottom of a well.'

 for sibling in soup.find(id="link3").previous_siblings: print(repr(sibling))

 ' and\n' Lacie ',\n' Elsie 'Once upon a time there were three little sisters; and their names were\n'

 last_a_tag = soup.find("a", id="link3") print(last_a_tag.next_sibling) print(last_a_tag.next_element)

 ; and they lived at the bottom of a well. Tillie

 last_a_tag.previous_element

 ' and\n' 

 for element in last_a_tag.next_elements: print(repr(element))

 'Tillie' ';\nand they lived at the bottom of a well.' '\n' 
...
 '...' '\n'