as I hold the string of hexadecimal format without encoding the string?

Question

The general problem is that I need the hexadecimal string stays in that format to assign it to a variable and not to save the coding?

no good:

>>> '\x61\x74'
'at'
>>> a = '\x61\x74'
>>> a
'at'

works well, but is not as:

>>> '\x61\x74'
'\x61\x74' ????????
>>> a = '\x61\x74'
>>> a
'\x61\x74' ????????

It's the same data. Why is that a problem? You are confusing Python's literal escape notation with the values they represent. — Martijn Pieters, Apr 12 '13 at 21:09
Maybe an explanation of Why would give us a clue to what your real problem is. — cmd, Apr 12 '13 at 21:14

score 4 · Answer 1 · edited May 23 '17 at 11:43

4

Use r prefix (explained on SO)

a = r'\x61\x74'
b = '\x61\x74'
print (a) #prints  \x61\x74
print (b) # prints at

edited May 23 '17 at 11:43

Community

1
1

answered Apr 12 '13 at 21:10

J0HN

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+1. You can also escape the backslashes… but using raw strings is easier, and more readable, so this is definitely the way to go. – abarnert Apr 12 '13 at 21:12
You can also convert `a` to `b` using `a.decode('string-escape')` (if this is needed...). – Bakuriu Apr 12 '13 at 21:12
@Bakuriu: No, `string-escape` would leave printable ASCII alone. – Martijn Pieters Apr 12 '13 at 21:26
@MartijnPieters Yes, but this is not the case. If `a` is an "hex-only" string, as the OP wanted, then `a.decode('string-escape')` does convert it to `b`. – Bakuriu Apr 13 '13 at 09:13
@Bakuriu: yes, `a` can decode to `b`, but `b` won't encode to `a`. – Martijn Pieters Apr 13 '13 at 10:27
@MartijnPieters I never mentioned converting `b` to `a`. – Bakuriu Apr 13 '13 at 11:19

score 3 · Accepted Answer · answered Apr 12 '13 at 21:11

It is the same data. Python lets you specify a literal string using different methods, one of which is to use escape codes to represent bytes.

As such, '\x61' is the same character value as 'a'. Python just chooses to show printable ASCII characters as printable ASCII characters instead of the escape code, just because that makes working with bytestrings that much easier.

If you need the literal slash, x character and the two digit 6 and 1 characters (so a string of length 4), you need to double the slash or use raw strings.

To illustrate:

>>> '\x61' == 'a'  # two notations for the same value
True
>>> len('\x61')    # it's just 1 character
1
>>> '\\x61'        # escape the escape
'\\x61'
>>> r'\x61'        # or use a raw literal instead
'\\x61'
>>> len('\\x61')   # which produces 4 characters
4

as I hold the string of hexadecimal format without encoding the string?

2 Answers2