爬虫必备—BeautifulSoup
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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。
1 from bs4 import BeautifulSoup 2 3 html_doc = """ 4 <html><head><title>The Dormouse\'s story</title></head> 5 <body> 6 asdf 7 <div class="title"> 8 <b>The Dormouse\'s story总共</b> 9 <h1>f</h1> 10 </div> 11 <div class="story">Once upon a time there were three little sisters; and their names were 12 <a class="sister0" id="link1">Els<span>f</span>ie</a>, 13 <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and 14 <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>; 15 and they lived at the bottom of a well.</div> 16 ad<br/>sf 17 <p class="story">...</p> 18 </body> 19 </html> 20 """ 21 22 soup = BeautifulSoup(html_doc, features="lxml") 23 # 找到第一个a标签 24 tag1 = soup.find(name=\'a\') 25 # 找到所有的a标签 26 tag2 = soup.find_all(name=\'a\') 27 # 找到id＝link2的标签 28 tag3 = soup.select(\'#link2\')
1. name，标签名称
1 # tag = soup.find(\'a\') 2 # name = tag.name # 获取 3 # print(name) 4 # tag.name = \'span\' # 设置 5 # print(soup)
2. attr，标签属性
1 # tag = soup.find(\'a\') 2 # attrs = tag.attrs # 获取 3 # print(attrs) 4 # tag.attrs = {\'ik\':123} # 设置 5 # tag.attrs[\'id\'] = \'iiiii\' # 设置 6 # print(soup)
3. children,所有子标签
1 # body = soup.find(\'body\') 2 # v = body.children
4. descendants,所有子子孙孙标签
1 # body = soup.find(\'body\') 2 # v = body.descendants
5. 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)
6. decompose,递归的删除所有的标签
1 # body = soup.find(\'body\') 2 # body.decompose() 3 # print(soup)
7. 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)
8. 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)
9. 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)
10. 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)
11. 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 11 12 # ####### 列表 ####### 13 # v = soup.find_all(name=[\'a\',\'div\']) 14 # print(v) 15 16 # v = soup.find_all(class_=[\'sister0\', \'sister\']) 17 # print(v) 18 19 # v = soup.find_all(text=[\'Tillie\']) 20 # print(v, type(v[0])) 21 22 23 # v = soup.find_all(id=[\'link1\',\'link2\']) 24 # print(v) 25 26 # v = soup.find_all(href=[\'link1\',\'link2\']) 27 # print(v) 28 29 # ####### 正则 ####### 30 import re 31 # rep = re.compile(\'p\') 32 # rep = re.compile(\'^p\') 33 # v = soup.find_all(name=rep) 34 # print(v) 35 36 # rep = re.compile(\'sister.*\') 37 # v = soup.find_all(class_=rep) 38 # print(v) 39 40 # rep = re.compile(\'http://www.oldboy.com/static/.*\') 41 # v = soup.find_all(href=rep) 42 # print(v) 43 44 # ####### 方法筛选 ####### 45 # def func(tag): 46 # return tag.has_attr(\'class\') and tag.has_attr(\'id\') 47 # v = soup.find_all(name=func) 48 # print(v) 49 50 51 # ## get,获取标签属性 52 # tag = soup.find(\'a\') 53 # v = tag.get(\'id\') 54 # print(v)
12. 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)
13. 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)
14. 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 5 # tag = soup.find(\'body\') 6 # for i,v in enumerate(tag): 7 # 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\'
1 # tag = soup.find(\'br\') 2 # v = tag.is_empty_element 3 # print(v)
16. 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
17. 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
18. 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)
19. 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)
20.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)
21.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)
22. 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)
23. 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)
24. 创建标签之间的关系（但不会改变标签的位置）
1 # tag = soup.find(\'div\') 2 # a = soup.find(\'a\') 3 # tag.setup(previous_sibling=a) 4 # print(tag.previous_sibling)
25. 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)
26. unwrap，去掉当前标签，将保留其包裹的标签
1 # tag = soup.find(\'a\') 2 # v = tag.unwrap() 3 # print(soup)
转载自：
http://www.cnblogs.com/wupeiqi/articles/6283017.html
更多参考：
Beautiful Soup 4.4.0 文档
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