> For the complete documentation index, see [llms.txt](https://jablack-programs.gitbook.io/python-notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jablack-programs.gitbook.io/python-notes/python-spider/beautifulsoup/sou-suo-wen-dang-shu/find_all/an-css-sou-suo.md). # 按CSS搜索 按照CSS类名搜索tag的功能非常实用,但标识CSS类名的关键字`class`在Python中是保留字,使用`class`做参数会导致语法错误.从Beautiful Soup的4.1.1版本开始,可以通过`class_`参数搜索有指定CSS类名的tag: ``` soup.find_all("a", class_="sister") # [Elsie, # Lacie, # Tillie] ``` `class_`参数同样接受不同类型的`过滤器`,字符串,正则表达式,方法或`True`: ``` soup.find_all(class_=re.compile("itl")) # [

The Dormouse's story

] def has_six_characters(css_class): return css_class is not None and len(css_class) == 6 soup.find_all(class_=has_six_characters) # [Elsie, # Lacie, # Tillie] ``` tag的`class`属性是[多值属性](http://beautifulsoup.readthedocs.io/zh_CN/latest/#id15).按照CSS类名搜索tag时,可以分别搜索tag中的每个CSS类名: ``` css_soup = BeautifulSoup('

') css_soup.find_all("p", class_="strikeout") # [

] css_soup.find_all("p", class_="body") # [

] ``` 搜索`class`属性时也可以通过CSS值完全匹配: ``` css_soup.find_all("p", class_="body strikeout") # [

] ``` 完全匹配`class`的值时,如果CSS类名的顺序与实际不符,将搜索不到结果: ``` soup.find_all("a", attrs={"class": "sister"}) # [Elsie, # Lacie, # Tillie] ```