如何使用xml.etree进行解析？Python

Question

Python 3.5

见代码

import urllib.request
from xml.etree import ElementTree as ET

url = 'http://www.sat.gob.mx/informacion_fiscal/tablas_indicadores/Paginas/tipo_cambio.aspx'


def conectar(url):
    page = urllib.request.urlopen(url)
    return page.read()

root = ET.fromstring(conectar(url))
s = root.findall("//*[contains(.,'21/')]")

需要解压缩'21/'，但返回此错误：

Erro:

Traceback (most recent call last):
  File "crawler.py", line 11, in <module>
    root = ET.fromstring(conectar(url))
  File "/home/rg3915/.pyenv/versions/3.5.0/lib/python3.5/xml/etree/ElementTree.py", line 1321, in XML
    parser.feed(text)
xml.etree.ElementTree.ParseError: unbound prefix: line 146, column 8

但我不知道如何解决这个错误。

Answer 1

你可以从以下方面开始：

import urllib2
from bs4 import BeautifulSoup

url = 'http://www.sat.gob.mx/informacion_fiscal/tablas_indicadores/Paginas/tipo_cambio.aspx'
response = urllib2.urlopen(url)
html = response.read()
dom = BeautifulSoup(html, 'html.parser')

tables = dom.find_all("table")
if len(tables):
    table = tables[0]
    print table

(用python 2.7测试)

Answer 2

当您试图解析的文档声明为xhtml时，由于未绑定前缀，它是无效的xml。

<gcse:search></gcse:search>

未为文档定义gcse ns前缀。

BeautifulSoup可能更适合您想要做的事情，因为它不会对文档100%的有效性感到费心。