Op 7/12/2022 om 4:37 schreef Jach Feng:
MRAB 在 2022年12月7日 星期三上午11:04:43 [UTC+8] 的信中寫道：
> On 2022-12-07 02:23, Jach Feng wrote:
> > s0 = r'\x0a'
> > At this moment it was done by
> >
> > def to1byte(matchobj):
> > ....return chr(int('0x' + matchobj.group(1), 16))
> > s1 = re.sub(r'\\x([0-9a-fA-F]{2})', to1byte, s0)
> >
> > But, is it that difficult on doing this simple thing?
> >
> You could try this:
>
> >>> s0 = r'\x0a'
> >>> ast.literal_eval('"%s"' % s0)
> '\n'
Not work in my system:-(
Python 3.8.8 (tags/v3.8.8:024d805, Feb 19 2021, 13:08:11) [MSC v.1928 32 bit
(Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> s0 = r'\x0a'
>>> import ast
>>> ast.literal_eval("%s" % s0)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Users\Jach\AppData\Local\Programs\Python\Python38-32\lib\ast.py",
line 59, in literal_eval
node_or_string = parse(node_or_string, mode='eval')
File "C:\Users\Jach\AppData\Local\Programs\Python\Python38-32\lib\ast.py",
line 47, in parse
return compile(source, filename, mode, flags,
File "<unknown>", line 1
\x0a
^
SyntaxError: unexpected character after line continuation character
You missed a pair of quotes. They are easily overlooked but very
important. The point is to wrap your string in another pair of quotes so
it becomes a valid Python string literal in a Python string which can
then be passed to ast.literal_eval(). Works for me:
In [7]: s0 = r'\x0a'
In [8]: import ast
In [9]: ast.literal_eval('"%s"' % s0)
Out[9]: '\n'
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