BeautifulSoup Python 文档中给出的示例不起作用

Question

我正在尝试 BeautifulSoup 文档中给出的示例，其中一个示例未给出预期结果

html_doc = """
<html><head><title>The Dormouse's story</title></head>

<p class="title"><b>The Dormouse's story</b></p>

<p class="story">Once upon a time there were three little sisters; and their     names were
 <a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>, 
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
<p class="story">...</p>
"""

from bs4 import BeautifulSoup
soup = BeautifulSoup(html_doc)

在示例中它说

soup.find_all('b')
# [<b>The Dormouse's story</b>]

但是当我尝试相同的命令时，出现如下错误

>>> soup.find_all('b')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'NoneType' object is not callable

但是 soup 对象不是 None

>>> soup

<html><head><title>The Dormouse's story</title></head>
<p class="title"><b>The Dormouse's story</b></p>
<p class="story">Once upon a time there were three little sisters; and their    
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
<p class="story">...</p>
</html>

我不确定为什么给定的示例不起作用。

Answer 1

您正在使用 BeautifulSoup 版本 three，而不是版本 4。

在BeautifulSoup3中，调用的方法是findAll()，而不是find_all()。因为使用一个不被识别的属性被翻译成soup.find('unrecognized_attribute')，你让BeautifulSoup找你第一个<find_all>HTML元素 ，不存在，因此返回 None。

改用BeautifulSoup 4:

from bs4 import BeautifulSoup

您几乎肯定会使用的地方：

from BeautifulSoup import BeautifulSoup  # version 3

您需要安装 beautifulsoup4 项目。

演示：

>>> html_doc = """
... <html><head><title>The Dormouse's story</title></head>
... 
... <p class="title"><b>The Dormouse's story</b></p>
... 
... <p class="story">Once upon a time there were three little sisters; and their     names were
...  <a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>, 
... <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
... <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
... <p class="story">...</p>
... """
>>> from bs4 import BeautifulSoup
>>> soup = BeautifulSoup(html_doc)
>>> soup.find_all('b')
[<b>The Dormouse's story</b>]
>>> from BeautifulSoup import BeautifulSoup
>>> soup = BeautifulSoup(html_doc)
>>> soup.find_all('b')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'NoneType' object is not callable

BeautifulSoup Python 文档中给出的示例不起作用

BeautifulSoup example given in Python documents not working

python

beautifulsoup