BeautifulSoup - lxml and html5lib parsers scraping differences

Question

I am using BeautifulSoup 4 with Python 2.7. I would like to extract certain elements from a website (Quantities, see the example bellow). For some reason, the lxml parser doesn't allow me to extract all of the desired elements from the page. It would print the first three elements only. I am trying to use the html5lib parser to see if I can extract all of them.

The page contains multiple items, with their price and quantities. A portion of the code containing the desired information for each of the item looks like this:

<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>

Let's consider the following three cases:

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

Prints:

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

Prints:

453 grams

CASE 3 - 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

I get the following error:

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

How do I have to adapt my code in order to extract the information that I want using the html5lib parser? I can see all of the desired information if I simply print the soup in the console after using the html5lib, so I figured it would allow me to get what I want. It is not the case for the lxml parser so I am also curious about the fact that the lxml parser doesn't seem to extract all of the Quantities using the lxml parser if I use:

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(' ')