使用 beautifulsoup 解析 HTML 页面 [英] Parsing HTML page using beautifulsoup

问题描述

我开始使用 beautifulsoup 来解析 HTML.
例如对于站点http://en.wikipedia.org/wiki/PLCB1">

I started working on beautifulsoup for parsing HTML.
for eg for site "http://en.wikipedia.org/wiki/PLCB1"

import sys
sys.setrecursionlimit(10000)

import urllib2, sys
from BeautifulSoup import BeautifulSoup

site= "http://en.wikipedia.org/wiki/PLCB1"
hdr = {'User-Agent': 'Mozilla/5.0'}
req = urllib2.Request(site,headers=hdr)
page = urllib2.urlopen(req)
soup = BeautifulSoup(page)

table = soup.find('table', {'class':'infobox'})
#print table
rows = table.findAll("th")
for x in rows:
    print "x - ", x.string

在某些有 url 的情况下，我得到的输出为 None.为什么会这样?

I am getting output as None in some cases of th where there is url. why it is so?

输出:

x -  Phospholipase C, beta 1 (phosphoinositide-specific)
x -  Identifiers
x -  None
x -  External IDs
x -  None
x -  None
x -  Molecular function
x -  Cellular component
x -  Biological process
x -  RNA expression pattern
x -  Orthologs
x -  Species
x -  None
x -  None
x -  None
x -  RefSeq (mRNA)
x -  RefSeq (protein)
x -  Location (UCSC)
x -  None

例如，在Location之后，还有一个包含pubmed search"但显示为None.我想知道它为什么会发生.

for example, after Location, there is one more th which contains "pubmed search" but appearing as None. I want to know why its happening.

和
第二:有没有办法在字典中获取 th 和各自的 td 以便于解析?

and
second : is there way to get th and respective td in dictionary so that it becomes easy to parse?

推荐答案

Element.string 仅在元素中直接存在文本时才包含一个值.不包括嵌套元素.

Element.string only contains a value if there is text directly in the element. Nested elements are not included.

如果您使用的是 BeautifulSoup 4，请使用 Element.stripped_strings 代替:

If you are using BeautifulSoup 4, use Element.stripped_strings instead:

print ''.join(x.stripped_strings)

对于 BeautifulSoup 3，您需要搜索所有文本元素:

For BeautifulSoup 3, you'll need to search for all text elements:

print ''.join([unicode(t).strip() for t in x.findAll(text=True)])

如果你想将 和 元素组合到一个字典中，你需要循环遍历所有 ; 元素，然后使用 .findNextSibling() 定位对应的 元素，并将其与上面的 .findAll(text=真的) 为自己建立字典的技巧:

If you want to combine <th> and <td> elements into a dictionary, you'd have loop over all <th> elements, then use .findNextSibling() to locate the corresponding <td> element, and combine that with the above .findAll(text=True) trick to build yourself a dictionary:

info = {}
rows = table.findAll("th")
for headercell in rows:
    valuecell = headercell.findNextSibling('td')
    if valuecell is None:
        continue
    header = ''.join([unicode(t).strip() for t in headercell.findAll(text=True)])
    value = ''.join([unicode(t).strip() for t in valuecell.findAll(text=True)])
    info[header] = value

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