Python: hex string to char

[AZzKikR]

In Python, I have the following string:

3C 4D 76 77 61 66

and so on.
These are ASCII characters and I'd like to output them as text.
I know how to extract each pair from a string, but how do I convert for instance the string "3C" to a character (like chr(0x3C))?

[pmasiar]

Did youchecked builtinn functions: http://docs.python.org/lib/built-in-funcs.html ?

[nanotube]

the following python session may be of help:

>>> import binascii
>>> binascii.unhexlify('3C 4D 76 77 61 66')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: Odd-length string
>>> binascii.unhexlify(''.join('3C 4D 76 77 61 66'.split()))
'<Mvwaf'
>>>

binascii.unhexlify() takes a hex string (no spaces between characters), and does exactly what you need.

[AZzKikR]

binascii.unhexlify() takes a hex string (no spaces between characters), and does exactly what you need.

Thanks, that was exactly what I needed!

[nanotube]

Thanks, that was exactly what I needed!

great. glad i could be of help

[ghostdog74]

def hextranslate(s):
        res = ""
        for i in range(len(s)/2):
                realIdx = i*2
                res = res + chr(int(s[realIdx:realIdx+2],16))
        return res

[nanotube]

def hextranslate(s):
        res = ""
        for i in range(len(s)/2):
                realIdx = i*2
                res = res + chr(int(s[realIdx:realIdx+2],16))
        return res

nice. but you forgot to account for the spaces between the hex pairs (the format of the OP's string). gotta either take them out with a split/join, or s/2/3/ in your code.

[ghostdog74]

nice. but you forgot to account for the spaces between the hex pairs

its left as an exercise for OP. where's the fun in learning if I do everything ?

[AZzKikR]

...
    res = res + chr(int(s[realIdx:realIdx+2],16))
...

Ah. The int(str, base) was what I was looking for as well. Java is my primary language, and it has a parsing mechanism from strings to integers using a base (10 for decimals, 16 for hex, 2 for binary). I was looking for something like that in Python, and I never knew int() could accept two arguments

[ghostdog74]

and I never knew int() could accept two arguments

for newer version of Python, yes.