使用Beautifulsoup的whitestaces类的正则表达式(Regular expression for class with whitespaces using Beautifulsoup)

 我发现方法BeautifulSoup.find（）按空格分割类属性。 在这种情况下，我无法使用正则表达式，如下面的代码所示。 你能不能帮助我找到所有'树儿'的元素： 
 
import re
from bs4 import BeautifulSoup 

r_html = "<div class='root'>" \
       "<div class='tree children1'>text children 1 </div>" \
       "<div class='tree children2'>text children 2 </div>" \
       "<div class='tree children3'>text children 3 </div>" \
   "</div>"

bs_tab = BeautifulSoup(r_html, "html.parser")
workspace_box_visible = bs_tab.findAll('div', {'class':'tree children1'})
print workspace_box_visible # result: [<div class="tree children1">textchildren 1 </div>]
workspace_box_visible = bs_tab.findAll('div', {'class':re.compile('^tree children\d')})
print workspace_box_visible # result: [] >>>> empty array because 
                                         #class name was splited by whitespace character<<<<

# >>>>>> print all element classes <<<<<<<
def print_class(class_):
    print class_
    return False

workspace_box_visible = bs_tab.find('div', {'class': print_class})

# expected: 
# root
# tree children1
# tree children2
# tree children3

# actual:
# root
# tree
# children1
# tree
# children2
# tree
# children3
 
 提前致谢， 
 
 ====评论========== 
 
 stackoverflow站点不允许添加超过500个字符的注释，所以我在这里添加了注释： 
 
 上面，举例说明了BeautifulSoup如何寻找所需的类。 
 
 但是，如果我有DOM结构，如： 
 
 r_html = "<div class='root'>" \
       "<div class='tree children'>zero</div>" \
       "<div class='tree children first'>first</div>" \
       "<div class='tree children second'>second</div>" \
       "<div class='tree children third'>third</div>" \
   "</div>"
 
 当需要选择具有类属性的控件时：' tree children '和' tree children first '，你的（Padraic Cunningham）帖子中描述的所有方法都不起作用。 
 
 我找到了使用正则表达式的解决方案： 
 
controls = bs_tab.findAll('div')
for control in controls:
    if re.search("^tree children|^tree children first", " ".join(control.attrs['class']  if control.attrs.has_key('class') else "")):
    print control
 
 另一个解决方案： 
 
bs_tab.findAll('div', class_='tree children') + bs_tab.findAll('div', class_='tree children first')
 
 我知道，这不是一个好的解决方案。 我希望BeautifulSoup模块有适当的方法。 

I found that method BeautifulSoup.find() splits class attribute by whitespaces. In that case I couldn't use regular expression as show in code below. Could you somebody help me to get right way find all 'tree children' elements:
 
import re
from bs4 import BeautifulSoup 

r_html = "<div class='root'>" \
       "<div class='tree children1'>text children 1 </div>" \
       "<div class='tree children2'>text children 2 </div>" \
       "<div class='tree children3'>text children 3 </div>" \
   "</div>"

bs_tab = BeautifulSoup(r_html, "html.parser")
workspace_box_visible = bs_tab.findAll('div', {'class':'tree children1'})
print workspace_box_visible # result: [<div class="tree children1">textchildren 1 </div>]
workspace_box_visible = bs_tab.findAll('div', {'class':re.compile('^tree children\d')})
print workspace_box_visible # result: [] >>>> empty array because 
                                         #class name was splited by whitespace character<<<<

# >>>>>> print all element classes <<<<<<<
def print_class(class_):
    print class_
    return False

workspace_box_visible = bs_tab.find('div', {'class': print_class})

# expected: 
# root
# tree children1
# tree children2
# tree children3

# actual:
# root
# tree
# children1
# tree
# children2
# tree
# children3
 
Thanks in advance,
 
==== comments ==========
 
stackoverflow site don't allow add comments more than 500 characters, so I added comments here: 
 
Above, it was example to show how to BeautifulSoup looking for required classes.
 
But, If I have DOM structure like: 
 
 r_html = "<div class='root'>" \
       "<div class='tree children'>zero</div>" \
       "<div class='tree children first'>first</div>" \
       "<div class='tree children second'>second</div>" \
       "<div class='tree children third'>third</div>" \
   "</div>"
 
and when need to select controls with class attributes: 'tree children' and 'tree children first', All of the methods described in your(Padraic Cunningham) post aren't work.
 
I found a solution with using regex: 
 
controls = bs_tab.findAll('div')
for control in controls:
    if re.search("^tree children|^tree children first", " ".join(control.attrs['class']  if control.attrs.has_key('class') else "")):
    print control
 
and another solution: 
 
bs_tab.findAll('div', class_='tree children') + bs_tab.findAll('div', class_='tree children first')
 
I know, it's not good solution. and I hope that BeautifulSoup module has appropriate method for that.

原文：https://stackoverflow.com/questions/38824121