reorder byte order in hex string (python)

Question

I want to build a small formatter in python giving me back the numeric values embedded in lines of hex strings.

It is a central part of my formatter and should be re

Answer 1

The swap from 'data_string_in_orig' to 'data_string_in_swapped' may also be done with comprehensions without using any imports:

>>> d = 'b62e000052e366667a66408d'
>>> "".join([m[2:4]+m[0:2] for m in [d[i:i+4] for i in range(0,len(d),4)]])
'2eb60000e3526666667a8d40'

The comprehension works for swapping byte order in hex strings representing 16-bit words. Modifying it for a different word-length is trivial. We can make a general hex digit order swap function also:

def swap_order(d, wsz=4, gsz=2 ):
    return "".join(["".join([m[i:i+gsz] for i in range(wsz-gsz,-gsz,-gsz)]) for m in [d[i:i+wsz] for i in range(0,len(d),wsz)]])

The input params are:

d : the input hex string

wsz: the word-size in nibbles (e.g for 16-bit words wsz=4, for 32-bit words wsz=8)

gsz: the number of nibbles which stay together (e.g for reordering bytes gsz=2, for reordering 16-bit words gsz = 4)