Question

我发现方法BeautifulSoup.find（）按空格分割类属性。在这种情况下，我无法在下面的代码中使用正则表达式。你能不能帮助我找到所有'树儿'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评论：

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：' 树儿 '和' 树儿童 ”，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

和另一种解决方案：

bs_tab.findAll('div', class_='tree children') + bs_tab.findAll('div', class_='tree children first')

我知道，这不是好办法。我希望BeautifulSoup模块有适当的方法。

Answer 1

根据html的结构，有几种不同的方式，它们是css类，所以你可以使用 .select 来使用class_=..或css选择器：

In [3]: bs_tab.find_all('div', class_="tree")
Out[3]: 
[<div class="tree children1">text children 1 </div>,
 <div class="tree children2">text children 2 </div>,
 <div class="tree children3">text children 3 </div>]

In [4]: bs_tab.select("div.tree")
Out[4]: 
[<div class="tree children1">text children 1 </div>,
 <div class="tree children2">text children 2 </div>,
 <div class="tree children3">text children 3 </div>]

但是，如果你在其他地方有另一个树类，那么也会找到它。

您可以使用选择器在类中查找包含 children 的div：

In [5]: bs_tab.select("div[class*=children]") 
Out[5]: 
[<div class="tree children1">text children 1 </div>,
 <div class="tree children2">text children 2 </div>,
 <div class="tree children3">text children 3 </div>]

但是，如果名称中还有其他带有子项的标记类，那么它们也会被选中。

您可以使用正则表达式更具体一点，并查找 children 后跟一个或多个数字：

In [6]: bs_tab.find_all('div', class_=re.compile("children\d+"))
Out[6]: 
[<div class="tree children1">text children 1 </div>,
 <div class="tree children2">text children 2 </div>,
 <div class="tree children3">text children 3 </div>]

或找到所有 div.tree的并查看标签中的姓氏[“class”] starstwith children < / em>的

In [7]: [t for t in bs_tab.select("div.tree") if t["class"][-1].startswith("children")] Out[7]: [<div class="tree children1">text children 1 </div>, <div class="tree children2">text children 2 </div>, <div class="tree children3">text children 3 </div>]

或寻找孩子，看看第一个css类名是否等于 tree

In [8]: [t for t in bs_tab.select("div[class*=children]") if t["class"][0] == "tree"] Out[8]: [<div class="tree children1">text children 1 </div>, <div class="tree children2">text children 2 </div>, <div class="tree children3">text children 3 </div>]

使用Beautifulsoup的具有空格的类的正则表达式

1 个答案: