Decoding specific escaped characters in a Python string

Question

I have a Python variable (named var) containing a string with the following literal data:

day\r\n\\night

in hex, it is:

64  61  79  5C  72  5C  6E  5C  5C  6E  69  67  68  74  07
d   a   y   \   r   \   n   \   \   n   i   g   h   t   BEL

I need to decode \\, \r and \n only.

The desired output (in hex):

64  61  79  0D  0A  5C  6E  69  67  68  74  07
d   a   y   CR  LF  \   n   i   g   h   t   BEL

Using decode doesn't work:

>>> print(var.decode('ascii'))
AttributeError: 'str' object has no attribute 'decode'. Did you mean: 'encode'?

Using regex to find and replace \\, \r and \n with their escaped values is unsuccessful, as the \n in \night is treated as a 0x0A.

Is it possible to specify which characters I want to decode, or is there a more appropriate module? I'm using Python 3.10.2.

Answer 1

Many thanks to everyone that contributed their answers, but none of them seemed to solve my issue completely. After long time of research I found this solution from sahil Kothiya (mirror) -- I modified it to resolve my specific issue:

import re, codecs

ESCAPE_SEQUENCE_RE = re.compile(r'''
    ( \\[\\nr]  # Single-character escapes
    )''', re.UNICODE | re.VERBOSE)

def decode_escapes(s):
    def decode_match(match):
        return codecs.decode(match.group(0), 'unicode-escape')
return ESCAPE_SEQUENCE_RE.sub(decode_match, s)

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Demonstration in IDLE:

Special characters shown in Notepad++:

Hex dump of output string:

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It even works with Unicode characters (an important component to my script).

Demonstration in IDLE:

Special characters shown in Notepad++:

Hex dump of output string: