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在我试图抓取的这个页面中，我想排除那些<td>具有属性的页面。

<td >点击这里查看阿根廷的综合区号列表</td>

我想知道使用什么函数来排除这个带有属性的标签

我的代码获取所有城市和区号

from bs4 import BeautifulSoup
import urllib2
import re

url = "http://www.howtocallabroad.com/argentina"
html_page = urllib2.urlopen(url)
soup = BeautifulSoup(html_page)

areatable = soup.find('table',{'id':'codes'})
if areatable is None:
    print "areatable is None"
else:
    d = {}

    def chunks(l, n):
            return [l[i : i + n] for i in range(0, len(l), n)]

    all_td = areatable.findAll('td')
    print all_td

    li = dict(chunks([i.text for i in all_td], 2))
    print li

但是当我尝试打印时li，它会引发异常：

Traceback (most recent call last):
  File "extract_table.py", line 21, in <module>
    li = dict(chunks([i.text for i in all_td], 2))
ValueError: dictionary update sequence element #30 has length 1; 2 is required

这是我打电话时得到的areatable.findAll('td')

[
<td>Buenos Aires</td>,
<td>11</td>,
<td>La Rioja</td>,
<td>380</td>,
<td>Salta</td>,
<td>387</td>,
<td>Bahia Blanca</td>,
<td>291</td>,
<td>Mar del Plata</td>,
<td>223</td>,
<td>San Juan</td>,
<td>264</td>,
<td>Catamarca<br/></td>,
<td>383</td>,
<td>Mendoza</td>,
<td>261</td>,
<td>San Luis</td>,
<td>266</td>,
<td>Comodoro Rivadavia</td>,
<td>297</td>,
<td>Mercedes/Prov. B.A.</td>,
<td>2324</td>,
<td>San Nicolas</td>,
<td>336</td>,
<td>Concordia</td>,
<td>345</td>,
<td>Neuquen</td>,
<td>299</td>,
<td>San Rafael</td>,
<td>260</td>,
<td>Cordoba</td>,
<td>351</td>,
<td>Parana</td>,
<td>343</td>,
<td>Santa Fe</td>,
<td>342</td>,
<td>Corrientes</td>,
<td>379</td>,
<td>Posadas</td>,
<td>376</td>,
<td>Santiago del Estero</td>,
<td>385</td>,
<td>Formosa</td>,
<td>370</td>,
<td>Resistencia</td>,
<td>362</td>,
<td>Santo Tome</td>,
<td>3756</td>,
<td>Jesus Maria</td>,
<td>3525</td>,
<td>Rio Cuarto</td>,
<td>358</td>,
<td>Tandil</td>,
<td>249</td>,
<td>La Plata</td>,
<td>221</td>,
<td>Rosario</td>,
<td>341</td>,
<td>Trelew</td>,
<td>280</td>,
<td colspan="6" id="more"><a href="http://www.cnc.gov.ar/infotecnica/numeracion/indicativosinter.asp" target="_blank">Click here</a> for a comprehensive area code list for Argentina</td>
]
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1 回答 1

4

问题是all_td是一个奇数长度，所以这个chunks函数不能完美地工作。这是一个简单的lambda函数，它找出标签是否没有属性，您可以使用它来仅捕获<td>stuff</td>标签：

>>> all_td = filter(lambda x: x.attrs == {}, all_td)
# all_td now contains [<td>Buenos Aires</td>, <td>11</td>, <td>La Rioja</td>, <td>380</td>, <td>Salta</td>, <td>387</td>, <td>Bahia Blanca</td>, <td>291</td>, <td>Mar del Plata</td>, <td>223</td>, <td>San Juan</td>, <td>264</td>, <td>Catamarca<br/></td>, <td>383</td>, <td>Mendoza</td>, <td>261</td>, <td>San Luis</td>, <td>266</td>, <td>Comodoro Rivadavia</td>, <td>297</td>, <td>Mercedes/Prov. B.A.</td>, <td>2324</td>, <td>San Nicolas</td>, <td>336</td>, <td>Concordia</td>, <td>345</td>, <td>Neuquen</td>, <td>299</td>, <td>San Rafael</td>, <td>260</td>, <td>Cordoba</td>, <td>351</td>, <td>Parana</td>, <td>343</td>, <td>Santa Fe</td>, <td>342</td>, <td>Corrientes</td>, <td>379</td>, <td>Posadas</td>, <td>376</td>, <td>Santiago del Estero</td>, <td>385</td>, <td>Formosa</td>, <td>370</td>, <td>Resistencia</td>, <td>362</td>, <td>Santo Tome</td>, <td>3756</td>, <td>Jesus Maria</td>, <td>3525</td>, <td>Rio Cuarto</td>, <td>358</td>, <td>Tandil</td>, <td>249</td>, <td>La Plata</td>, <td>221</td>, <td>Rosario</td>, <td>341</td>, <td>Trelew</td>, <td>280</td>]

简单地说，如果标签没有属性，该lambda函数将返回。所做的是遍历 中的每个元素True，并对每个元素运行 lambda 函数。如果 lambda 函数返回给定标记，则将其从列表中删除。返回一个新列表。filter()all_tdFalse

现在调用块时，列表中的元素数量将是偶数，因此不会出现错误。

于 2013-06-06T08:29:02.840 回答