Python writing hex/bytes to file

[v1rati]

Hi,

Right now I'm trying to write a list of hex values (strings) to a disk file in Python 3.1.

['AB', 'EC', 'CD', 'AB', 'ED', 'EB', 'DB', 'AB', 'EC']

I tried adding \x before each one and then writing it to file, but it's writing it literally as '\xAB\xEC\xCD\xAB\xED\xEB\xDB\xAB\xEC'.

What do I need to do to write it as bytes?

Thanks.

[Vaphell]

http://linux.byexamples.com/archives...g-binary-file/

[wmcbrine]

You might want to post more of your code to illustrate exactly what you've tried.

[v1rati]

http://linux.byexamples.com/archives...g-binary-file/

I tried that an it spat out:

TypeError: must be bytes or buffer, not str

You might want to post more of your code to illustrate exactly what you've tried.

bitlist = ['AB', 'EC', 'CD', 'AB', 'ED', 'EB', 'DB', 'AB', 'EC']
for bit in bitlist:
    bitstring += r'\x' + bit
bitout = open('bitout', 'wb')
bitout.write(bitstring)

[DaithiF]

the binascii module can help:

import binascii
bitlist = ['AB', 'EC', 'CD', 'AB', 'ED', 'EB', 'DB', 'AB', 'EC']
bytes = binascii.a2b_hex(''.join(bitlist))
bitout.write(bytes)

[ssam]

if those byte represent values you may find http://docs.python.org/library/struct.html useful

[wmcbrine]

bitlist = ['AB', 'EC', 'CD', 'AB', 'ED', 'EB', 'DB', 'AB', 'EC']
for bit in bitlist:
    bitstring += r'\x' + bit
bitout = open('bitout', 'wb')
bitout.write(bitstring)

So, what you're doing here is creating strings that start with a literal backslash. These are not then evaluated into byte values. (Think about it -- at what point would that happen?)

You might try something more like this:

for bit in bitlist:
    bitstring += chr(int(bit, 16))