BeautifulSoup - lxml和html5lib解析器抓取差异

Question

我使用BeautifulSoup 4与Python 2.7。我想从一个网站提取某些元素(数量，见下面的例子)。由于某种原因，lxml解析器不允许我从页面中提取所需的所有元素。它将只打印前三个元素。我正试图使用html5lib解析器，看看我是否可以提取所有的。

页面包含多个项目，以及它们的价格和数量。包含每个项目所需信息的代码部分如下所示:

<td class="size-price last first" colspan="4">
                    <span>453 grams </span>
            <span> <span class="strike">$619.06</span> <span class="price">$523.91</span>
                    </span>
                </td>

让我们考虑以下三种情况:

CASE 1 - DATA:

#! /usr/bin/python
from bs4 import BeautifulSoup
data = """
<td class="size-price last first" colspan="4">
                    <span>453 grams </span>
            <span> <span class="strike">$619.06</span> <span class="price">$523.91</span>
                    </span>
                </td>"""                
soup = BeautifulSoup(data)
print soup.td.span.text

打印:

453 grams 

CASE 2 - LXML:

#! /usr/bin/python
from bs4 import BeautifulSoup
from urllib import urlopen
webpage = urlopen('The URL goes here')
soup=BeautifulSoup(webpage, "lxml")
print soup.find('td', {'class': 'size-price'}).span.text

打印:

453 grams

CASE - HTML5LIB:

#! /usr/bin/python
from bs4 import BeautifulSoup
from urllib import urlopen
webpage = urlopen('The URL goes here')
soup=BeautifulSoup(webpage, "html5lib")
print soup.find('td', {'class': 'size-price'}).span.text

我得到以下错误:

Traceback (most recent call last):
  File "C:UsersDomPython-CodesrcTesting-Code.py", line 6, in <module>
    print soup.find('td', {'class': 'size-price'}).span.text
AttributeError: 'NoneType' object has no attribute 'span'

我如何适应我的代码，以便提取我想要使用html5lib解析器的信息?如果在使用html5lib之后在控制台中简单地打印soup，我就可以看到所有想要的信息，因此我认为它将允许我得到我想要的。这不是lxml解析器的情况下，所以我也很好奇的事实，lxml解析器似乎没有提取所有的数量使用lxml解析器，如果我使用:

print [td.span.text for td in soup.find_all('td', {'class': 'size-price'})]

Answer 1

from lxml import etree
html = 'your html'
tree = etree.HTML(html)
tds = tree.xpath('.//td[@class="size-price last first"]')
for td in tds:
    price = td.xpath('.//span[@class="price"]')[0].text
    strike = td.xpath('.//span[@class="strike"]')[0].text
    spans = td.xpath('.//span')
    quantity = [i.text for i in spans if 'grams' in i.text][0].strip(' ')

Answer 2

尝试如下:

    from bs4 import BeautifulSoup
    data = """
    <td class="size-price last first" colspan="4">
                <span>453 grams </span>
        <span> <span class="strike">$619.06</span> <span 
    class="price">$523.91</span>
                </span>
            </td>"""                
    soup = BeautifulSoup(data)
    text = soup.get_text(strip=True)
    print text