将带有转义字符和ASCII值的字符串转换为十六进制

Question

I have the following string which contains escaped HEX values and ASCII characters

"\01B\2E\00   k\00"

A backslash means that the next two characters are HEX values, everything else in the string is ASCII

The goal is to convert the entire string into all HEX values

end result:

"\01\42\2E\00\20\20\20\6B\00"

::edit::

I had tried the following:

s = "\01B\2E\00   k\00"
r = [ ]

for x in s:
    r.append(x.encode("hex"))

print r

the problem was the values (ex: \\1E ) were being interpreted as \\x01 and E

Then i ran into the following question online came to post an update, and realized my question was already answered.

Thanks

Answer 1

Here is a Python string that contains escaped hex values and ascii characters.

>>> s = r"\01B\2E\00   k\00"
>>> s
'\\01B\\2E\\00   k\\00'
>>> print(s)
\01B\2E\00   k\00

First we decode with the string-escape codec to convert the escaped hex values into the character representation. In order to use string-escape with hexadecimal values, we need to use \\x for the escape indicator rather than just \\ (which implies octal values iirc)

>>> escaped = s.replace('\\', '\\x').decode('string-escape')
>>> escaped
'\x01B.\x00   k\x00'
>>> print escaped
B.   k

Some of our characters are not printable. But the result is that all our characters are hex values/characters.

If you want to convert all the characters in the escaped hex representation , however, you will need to convert explicitly into hex values:

>>> h = ''.join('\\' + char.encode('hex') for char in escaped)
>>> h
'\\01\\42\\2e\\00\\20\\20\\20\\6b\\00'
>>> print h
\01\42\2e\00\20\20\20\6b\00

Note that bytes-to-bytes encoding is deprecated in Python3. You would instead use the binascii .hexlify and .unhexlify methods.

Answer 2

You could use re.split() to tokenize the string in Python:

>>> import re
>>> data = r"\01B\2E\00   k\00"
>>> L = re.split(r'((?:\\{hex}{hex})+)'.format(hex='[0-9a-fA-F]'), data)
>>> L
['', '\\01', 'B', '\\2E\\00', '   k', '\\00', '']
>>> L[::2] = [''.join('\\' + c.encode('hex') for c in s) for s in L[::2]]
>>> print ''.join(L)
\01\42\2E\00\20\20\20\6b\00