I have a long sequence of hex digits in a string, such as

000000000000484240FA063DE5D0B744ADBED63A81FAEA390000C8428640A43D5005BD44

only much longer, several kilobytes. Is there a builtin way to convert this to a bytes object in python 2.6/3?

Works in Python 2.7 and higher including python3:

result = bytearray.fromhex('deadbeef')

Note: There seems to be a bug with the bytearray.fromhex() function in Python 2.6. The python.org documentation states that the function accepts a string as an argument, but when applied, the following error is thrown:

>>> bytearray.fromhex('B9 01EF')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: fromhex() argument 1 must be unicode, not str`

result = bytes.fromhex(some_hex_string)

You can do this with the hex codec. ie:

>>> s="000000000000484240FA063DE5D0B744ADBED63A81FAEA390000C8428640A43D5005BD44"
>>> s.decode('hex')
'\x00\x00\x00\x00\x00\[email protected]\xfa\x06=\xe5\xd0\xb7D\xad\xbe\xd6:\x81\xfa\xea9\x00\x00\xc8B\[email protected]\xa4=P\x05\xbdD'

Try the binascii module

from binascii import unhexlify
b = unhexlify(myhexstr)

import binascii

binascii.a2b_hex(hex_string)

Thats the way I did it.