Question

有没有办法在Python 2中重现py3的不在repr（）中转义Unicode？

$ python3
>>> s="…\n…"
>>> print(repr(s))
'…\n…'

但

$ python2
>>> s=u"…\n…"
>>> print repr(s)
u'\u2026\n\u2026'

我想要

u'…\n…'

我设法提出的解决方案是

#!/usr/bin/python

import re
_uregex=re.compile("\\\\([^uU])")

def _ureplace(x):
    x = x.group(1)
    if x == "\\":
        return "\\\\\\\\" # Eight of them. Required.
    return "\\\\"+x
def urepr(x):
    return _uregex.sub(_ureplace,repr(x)).decode("unicode-escape")

s = u"\u2026\n\u2026"
print(urepr(s))

但我想知道是否有更好的方法来做到这一点 - 逃避一切，只是为了解决所有问题，似乎相当浪费。而且速度慢（我需要这个以便快速编写很多大对象并重新编写日志文件）。

Answer 1

我不认为Python 2提供了这样做的方法，但是编写自己的代码很容易。

import unicodedata

def unichr_repr(ch):
    if ch == '\\':
        return '\\\\'
    elif ch == "'":
        return "\\'"
    category = unicodedata.category(ch)
    if category == 'Cc':
        if ch == '\n':
            return '\\n'
        n = ord(ch)
        if n < 0x100:
            return '\\x%02x' % n
        if n < 0x10000:
            return '\\u%04x' % n
        return '\\U%08x' % n
    return ch

def unistr_repr(s):
    return "'" + ''.join(unichr_repr(ch) for ch in s) + "'"

Answer 2

这是一个更完整的解决方案，适用于unicode字符串列表：

import reprlib
import sys

class URepr(reprlib.Repr):
    """
    On python 3, repr returns unicode objects, which means that non-ASCII
    characters are rendered in human readable form.

    This provides a similar facility on python 2.

    Additionally, on python 3, it prefixes unicode repr with a u, such that
    the returned repr is a valid unicode literal on both python 2 and python
    3
    """

    # From https://github.com/python/cpython/blob/3.6/Objects/unicodectype.c#L147-L1599
    nonprintable_categories = ('Cc', 'Cf', 'Cs', 'Co', 'Cn', 'Zl', 'Zp', 'Zs')

    if sys.version_info.major >= 3:
        def repr_str(self, obj, level):
            return 'u' + super().repr_str(obj, level)
    else:
        def repr_unicode(self, obj, level):
            def _escape(ch):
                # printable characters that have special meanings in literals
                if ch == u'\\':
                    return u'\\\\'
                elif ch == u"'":
                    return u"\\'"

                # non-printable characters - convert to \x.., \u...., \U........
                category = unicodedata.category(ch)
                if category in self.nonprintable_categories:
                    return ch.encode('unicode-escape').decode('ascii')

                # everything else
                return ch

            return u"u'{}'".format(''.join(_escape(c) for c in obj))

可用作：

repr = URepr().repr

repr([u'hello', u'world'])

Answer 3

虽然我了解您希望使用您的方法，但如果您将Unicode作为数值接收，我可以建议使用函数chr()吗？

Answer 4

尝试

repr(string).decode("utf-8")

我怎么不逃脱python2中的unicode？

4 个答案: