How to byte-swap a 32-bit integer in python?

Question

Take this example:

i = 0x12345678
print(\"{:08x}\".format(i))
   # shows 12345678
i = swap32(i)
print(\"{:08x}\".format(i))
   # should print 78563412
         


        

Answer 1

From python 3.2 you can define function swap32() as the following:

def swap32(x):
    return int.from_bytes(x.to_bytes(4, byteorder='little'), byteorder='big', signed=False)

It uses array of bytes to represent the value and reverses order of bytes by changing endianness during conversion back to integer.