BeautifulSoup

BeautifulSoup

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爬虫必备—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，之后便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。

 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')

 # 找到所有的a标签

 tag2 = soup.find_all(name='a')

 # 找到id＝link2的标签

 tag3 = soup.select('#link2')

简单示例

1. name，标签名称

 # tag = soup.find('a')

 # name = tag.name # 获取

 # print(name)

 # tag.name = 'span' # 设置

 # print(soup)

2. attr，标签属性

 # tag = soup.find('a')

 # attrs = tag.attrs    # 获取

 # print(attrs)

 # tag.attrs = {'ik':123} # 设置

 # tag.attrs['id'] = 'iiiii' # 设置

 # print(soup)

3. children,所有子标签

 # body = soup.find('body')

 # v = body.children

4. descendants,所有子子孙孙标签

 # body = soup.find('body')

 # v = body.descendants

5. clear,将标签的所有子标签全部清空（保留标签名）

 # tag = soup.find('body')

 # tag.clear()

 # print(soup)

6. decompose,递归的删除所有的标签

 # body = soup.find('body')

 # body.decompose()

 # print(soup)

7. extract,递归的删除所有的标签，并获取删除的标签

 # body = soup.find('body')

 # v = body.extract()

 # print(soup)

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

 # body = soup.find('body')

 # v = body.decode()

 # v = body.decode_contents()

 # print(v)

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

 # body = soup.find('body')

 # v = body.encode()

 # v = body.encode_contents()

 # print(v)

10. find,获取匹配的第一个标签

 # tag = soup.find('a')

 # print(tag)

 # tag = soup.find(name='a', attrs={'class': 'sister'}, recursive=True, text='Lacie')

 # tag = soup.find(name='a', class_='sister', recursive=True, text='Lacie')

 # print(tag)

11. find_all,获取匹配的所有标签

 # tags = soup.find_all('a')

 # print(tags)

 # tags = soup.find_all('a',limit=1)

 # print(tags)

 # tags = soup.find_all(name='a', attrs={'class': 'sister'}, recursive=True, text='Lacie')

 # # tags = soup.find(name='a', class_='sister', recursive=True, text='Lacie')

 # print(tags)

 # ####### 列表 #######

 # v = soup.find_all(name=['a','div'])

 # print(v)

 # v = soup.find_all(class_=['sister0', 'sister'])

 # print(v)

 # v = soup.find_all(text=['Tillie'])

 # print(v, type(v[0]))

 # v = soup.find_all(id=['link1','link2'])

 # print(v)

 # v = soup.find_all(href=['link1','link2'])

 # print(v)

 # ####### 正则 #######

 import re

 # rep = re.compile('p')

 # rep = re.compile('^p')

 # v = soup.find_all(name=rep)

 # print(v)

 # rep = re.compile('sister.*')

 # v = soup.find_all(class_=rep)

 # print(v)

 # rep = re.compile('http://www.oldboy.com/static/.*')

 # v = soup.find_all(href=rep)

 # print(v)

 # ####### 方法筛选 #######

 # def func(tag):

 # return tag.has_attr('class') and tag.has_attr('id')

 # v = soup.find_all(name=func)

 # print(v)

 # ## get,获取标签属性

 # tag = soup.find('a')

 # v = tag.get('id')

 # print(v)

12. has_attr,检查标签是否具有该属性

 # tag = soup.find('a')

 # v = tag.has_attr('id')

 # print(v)

13. get_text,获取标签内部文本内容

 # tag = soup.find('a')

 # v = tag.get_text('id')

 # print(v)

14. index,检查标签在某标签中的索引位置

 # tag = soup.find('body')

 # v = tag.index(tag.find('div'))

 # print(v)

 # tag = soup.find('body')

 # for i,v in enumerate(tag):

 # print(i,v)

15. 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'

 # tag = soup.find('br')

 # v = tag.is_empty_element

 # print(v)

16. 当前的关联标签

 # soup.next

 # soup.next_element

 # soup.next_elements

 # soup.next_sibling

 # soup.next_siblings

 #

 # tag.previous

 # tag.previous_element

 # tag.previous_elements

 # tag.previous_sibling

 # tag.previous_siblings

 #

 # tag.parent

 # tag.parents

17. 查找某标签的关联标签

 # tag.find_next(...)

 # tag.find_all_next(...)

 # tag.find_next_sibling(...)

 # tag.find_next_siblings(...)

 # tag.find_previous(...)

 # tag.find_all_previous(...)

 # tag.find_previous_sibling(...)

 # tag.find_previous_siblings(...)

 # tag.find_parent(...)

 # tag.find_parents(...)

 # 参数同find_all

18. select,select_one, CSS选择器

 soup.select("title")

 soup.select("p nth-of-type(3)")

 soup.select("body a")

 soup.select("html head title")

 tag = soup.select("span,a")

 soup.select("head > title")

 soup.select("p > a")

 soup.select("p > a:nth-of-type(2)")

 soup.select("p > #link1")

 soup.select("body > a")

 soup.select("#link1 ~ .sister")

 soup.select("#link1 + .sister")

 soup.select(".sister")

 soup.select("[class~=sister]")

 soup.select("#link1")

 soup.select("a#link2")

 soup.select('a[href]')

 soup.select('a[href="http://example.com/elsie"]')

 soup.select('a[href^="http://example.com/"]')

 soup.select('a[href$="tillie"]')

 soup.select('a[href*=".com/el"]')

 from bs4.element import Tag

 def default_candidate_generator(tag):

     for child in tag.descendants:

         if not isinstance(child, Tag):

             continue

         if not child.has_attr('href'):

             continue

         yield child

 tags = soup.find('body').select("a", _candidate_generator=default_candidate_generator)

 print(type(tags), tags)

 from bs4.element import Tag

 def default_candidate_generator(tag):

     for child in tag.descendants:

         if not isinstance(child, Tag):

             continue

         if not child.has_attr('href'):

             continue

         yield child

 tags = soup.find('body').select("a", _candidate_generator=default_candidate_generator, limit=1)

 print(type(tags), tags)

19. 标签的内容

 # tag = soup.find('span')

 # print(tag.string)          # 获取

 # tag.string = 'new content' # 设置

 # print(soup)

 # tag = soup.find('body')

 # print(tag.string)

 # tag.string = 'xxx'

 # print(soup)

 # tag = soup.find('body')

 # v = tag.stripped_strings  # 递归内部获取所有标签的文本

 # print(v)

20.append在当前标签内部追加一个标签

 # tag = soup.find('body')

 # tag.append(soup.find('a'))

 # print(soup)

 #

 # from bs4.element import Tag

 # obj = Tag(name='i',attrs={'id': 'it'})

 # obj.string = '我是一个新来的'

 # tag = soup.find('body')

 # tag.append(obj)

 # print(soup)

21.insert在当前标签内部指定位置插入一个标签

 # from bs4.element import Tag

 # obj = Tag(name='i', attrs={'id': 'it'})

 # obj.string = '我是一个新来的'

 # tag = soup.find('body')

 # tag.insert(2, obj)

 # print(soup)

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

 # from bs4.element import Tag

 # obj = Tag(name='i', attrs={'id': 'it'})

 # obj.string = '我是一个新来的'

 # tag = soup.find('body')

 # # tag.insert_before(obj)

 # tag.insert_after(obj)

 # print(soup)

23. replace_with 在当前标签替换为指定标签

 # from bs4.element import Tag

 # obj = Tag(name='i', attrs={'id': 'it'})

 # obj.string = '我是一个新来的'

 # tag = soup.find('div')

 # tag.replace_with(obj)

 # print(soup)

24. 创建标签之间的关系（但不会改变标签的位置）

 # tag = soup.find('div')

 # a = soup.find('a')

 # tag.setup(previous_sibling=a)

 # print(tag.previous_sibling)

25. wrap，将指定标签把当前标签包裹起来

 # from bs4.element import Tag

 # obj1 = Tag(name='div', attrs={'id': 'it'})

 # obj1.string = '我是一个新来的'

 #

 # tag = soup.find('a')

 # v = tag.wrap(obj1)

 # print(soup)

 # tag = soup.find('a')

 # v = tag.wrap(soup.find('p'))

 # print(soup)

26. unwrap，去掉当前标签，将保留其包裹的标签

 # tag = soup.find('a')

 # v = tag.unwrap()

 # print(soup)

转载自：

http://www.cnblogs.com/wupeiqi/articles/6283017.html

更多参考：

Beautiful Soup 4.4.0 文档

05-11 15:17
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