How to convert a raw string r'\xdd' to '\xdd' more gracefully?

[Weatherby,Gerard]

That’s actually more of a shell question than a Python question. How you pass certain control characters is going to depend on the shell, operating system, and possibly the keyboard you’re using. (e.g. https://www.alt-codes.net).

Here’s a sample program. The dashes are to help show the boundaries of the string

#!/usr/bin/env python3
import argparse
import logging


parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument('data')
args = parser.parse_args()
print(f'Input\n: -{args.data}- length {len(args.data)}')
for c in args.data:
    print(f'{ord(c)} ',end='')
print()


Using bash on Linux:

./cl.py '^M
'
Input
  -
- length 3
13 32 10


From: Python-list <python-list-bounces+gweatherby=uchc.edu at python.org> on behalf of Jach Feng <jfong at ms4.hinet.net>
Date: Thursday, December 8, 2022 at 9:31 PM
To: python-list at python.org <python-list at python.org>
Subject: Re: How to convert a raw string r'xdd' to 'xdd' more gracefully?
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Jach Feng 在 2022年12月7日 星期三上午10:23:20 [UTC+8] 的信中寫道：
> 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?
>
> --Jach
The whold story is,

I had a script which accepts an argparse's positional argument. I like this argument may have control character embedded in when required. So I make a post "How to enter escape character in a positional string argument from the command line? on DEC05. But there is no response. I assume that there is no way of doing it and I have to convert it later after I get the whole string from the command line.

I made this convertion using the chr(int(...)) method but not satisfied with. That why this post came out.

At this moment the conversion is done almost the same as Peter's codecs.decode() method but without the need of importing codecs module:-)

def to1byte(matchobj):
....return matchobj.group(0).encode().decode("unicode-escape")
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