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。
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：
