在 Python 中将 XML/HTML 实体转换为 Unicode 字符串

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You could find an answer here -- Getting international characters from a web page?

EDIT: It seems like BeautifulSoup doesn't convert entities written in hexadecimal form. It can be fixed:

import copy, re
from BeautifulSoup import BeautifulSoup


hexentityMassage = copy.copy(BeautifulSoup.MARKUP_MASSAGE)
# replace hexadecimal character reference by decimal one
hexentityMassage += [(re.compile('&#x([^;]+);'),
lambda m: '&#%d;' % int(m.group(1), 16))]


def convert(html):
return BeautifulSoup(html,
convertEntities=BeautifulSoup.HTML_ENTITIES,
markupMassage=hexentityMassage).contents[0].string


html = '<html>&#x01ce;&#462;</html>'
print repr(convert(html))
# u'\u01ce\u01ce'

EDIT:

unescape() function mentioned by @dF which uses htmlentitydefs standard module and unichr() might be more appropriate in this case.

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Use the builtin unichr -- BeautifulSoup isn't necessary:

>>> entity = '&#x01ce'
>>> unichr(int(entity[3:],16))
u'\u01ce'

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Python has the htmlentitydefs module, but this doesn't include a function to unescape HTML entities.

Python developer Fredrik Lundh (author of elementtree, among other things) has such a function on his website, which works with decimal, hex and named entities:

import re, htmlentitydefs


##
# Removes HTML or XML character references and entities from a text string.
#
# @param text The HTML (or XML) source text.
# @return The plain text, as a Unicode string, if necessary.


def unescape(text):
def fixup(m):
text = m.group(0)
if text[:2] == "&#":
# character reference
try:
if text[:3] == "&#x":
return unichr(int(text[3:-1], 16))
else:
return unichr(int(text[2:-1]))
except ValueError:
pass
else:
# named entity
try:
text = unichr(htmlentitydefs.name2codepoint[text[1:-1]])
except KeyError:
pass
return text # leave as is
return re.sub("&#?\w+;", fixup, text)

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This is a function which should help you to get it right and convert entities back to utf-8 characters.

def unescape(text):
"""Removes HTML or XML character references
and entities from a text string.
@param text The HTML (or XML) source text.
@return The plain text, as a Unicode string, if necessary.
from Fredrik Lundh
2008-01-03: input only unicode characters string.
http://effbot.org/zone/re-sub.htm#unescape-html
"""
def fixup(m):
text = m.group(0)
if text[:2] == "&#":
# character reference
try:
if text[:3] == "&#x":
return unichr(int(text[3:-1], 16))
else:
return unichr(int(text[2:-1]))
except ValueError:
print "Value Error"
pass
else:
# named entity
# reescape the reserved characters.
try:
if text[1:-1] == "amp":
text = "&amp;amp;"
elif text[1:-1] == "gt":
text = "&amp;gt;"
elif text[1:-1] == "lt":
text = "&amp;lt;"
else:
print text[1:-1]
text = unichr(htmlentitydefs.name2codepoint[text[1:-1]])
except KeyError:
print "keyerror"
pass
return text # leave as is
return re.sub("&#?\w+;", fixup, text)

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Not sure why the Stack Overflow thread does not include the ';' in the search/replace (i.e. lambda m: '&#%d*;*') If you don't, BeautifulSoup can barf because the adjacent character can be interpreted as part of the HTML code (i.e. &#39B for &#39Blackout).

This worked better for me:

import re
from BeautifulSoup import BeautifulSoup


html_string='<a href="/cgi-bin/article.cgi?f=/c/a/2010/12/13/BA3V1GQ1CI.DTL"title="">&#x27;Blackout in a can; on some shelves despite ban</a>'


hexentityMassage = [(re.compile('&#x([^;]+);'),
lambda m: '&#%d;' % int(m.group(1), 16))]


soup = BeautifulSoup(html_string,
convertEntities=BeautifulSoup.HTML_ENTITIES,
markupMassage=hexentityMassage)

The int(m.group(1), 16) converts the number (specified in base-16) format back to an integer.
m.group(0) returns the entire match, m.group(1) returns the regexp capturing group
Basically using markupMessage is the same as:
html_string = re.sub('&#x([^;]+);', lambda m: '&#%d;' % int(m.group(1), 16), html_string)

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An alternative, if you have lxml:

>>> import lxml.html
>>> lxml.html.fromstring('&#x01ce').text
u'\u01ce'

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最佳答案

The standard lib’s very own HTMLParser has an undocumented function unescape() which does exactly what you think it does:

up to Python 3.4:

import HTMLParser
h = HTMLParser.HTMLParser()
h.unescape('&copy; 2010') # u'\xa9 2010'
h.unescape('&#169; 2010') # u'\xa9 2010'

Python 3.4+:

import html
html.unescape('&copy; 2010') # u'\xa9 2010'
html.unescape('&#169; 2010') # u'\xa9 2010'

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If you are on Python 3.4 or newer, you can simply use the html.unescape:

import html


s = html.unescape(s)

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Another solution is the builtin library xml.sax.saxutils (both for html and xml). However, it will convert only &gt, &amp and &lt.

from xml.sax.saxutils import unescape


escaped_text = unescape(text_to_escape)

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Here is the Python 3 version of dF's answer:

import re
import html.entities


def unescape(text):
"""
Removes HTML or XML character references and entities from a text string.


:param text:    The HTML (or XML) source text.
:return:        The plain text, as a Unicode string, if necessary.
"""
def fixup(m):
text = m.group(0)
if text[:2] == "&#":
# character reference
try:
if text[:3] == "&#x":
return chr(int(text[3:-1], 16))
else:
return chr(int(text[2:-1]))
except ValueError:
pass
else:
# named entity
try:
text = chr(html.entities.name2codepoint[text[1:-1]])
except KeyError:
pass
return text # leave as is
return re.sub("&#?\w+;", fixup, text)

The main changes concern htmlentitydefs that is now html.entities and unichr that is now chr. See this Python 3 porting guide.