byte reverse AB CD to CD AB with python

Question

I have a .bin file, and I want to simply byte reverse the hex data. Say for instance @ 0x10 it reads AD DE DE C0, want it to read DE AD C0 DE.

I know there is a simp

Answer 1

In Python 3.4 you can use this:

>>> data = b'\xAD\xDE\xDE\xC0'
>>> swap_data = bytearray(data)
>>> swap_data.reverse()

the result is

bytearray(b'\xc0\xde\xde\xad')

Answer 2

In Python 2, the binary file gets read as a string, so string slicing should easily handle the swapping of adjacent bytes:

>>> original = '\xAD\xDE\xDE\xC0'
>>> ''.join([c for t in zip(original[1::2], original[::2]) for c in t])
'\xde\xad\xc0\xde'

In Python 3, the binary file gets read as bytes. Only a small modification is need to build another array of bytes:

>>> original = b'\xAD\xDE\xDE\xC0'
>>> bytes([c for t in zip(original[1::2], original[::2]) for c in t])
b'\xde\xad\xc0\xde'

You could also use the < and > endianess format codes in the struct module to achieve the same result:

>>> struct.pack('<2h', *struct.unpack('>2h', original))
'\xde\xad\xc0\xde'

Happy byte swapping :-)

Answer 3

Python has a list operator to reverse the values of a list --> nameOfList[::-1]

So, I might store the hex values as string and put them into a list then try something like:

def reverseList(aList):
rev = aList[::-1]
outString = ""
for el in rev:
    outString += el + " "
return outString

Answer 4

data = b'\xAD\xDE\xDE\xC0'
reversed_data = data[::-1]
print(reversed_data)
# b'\xc0\xde\xde\xad'