Martijn Pieters' timings are a bit different to mine:
def bxor_add(b1, b2): # use xor for bytes
result = b""
for b1, b2 in zip(b1, b2):
result += bytes([b1 ^ b2])
return result
def bxor_inplace(b1, b2):
result = bytearray(b1)
for i, b in enumerate(b2):
result[i] ^= b
return bytes(result)
def bxor_join(b1, b2): # use xor for bytes
parts = []
for b1, b2 in zip(b1, b2):
parts.append(bytes([b1 ^ b2]))
return b''.join(parts)
def bxor_append(b1, b2): # use xor for bytes
result = bytearray()
for b1, b2 in zip(b1, b2):
result.append(b1 ^ b2)
return bytes(result)
#>>>
from os import urandom
from timeit import Timer
from functools import partial
first_random = urandom(200000)
second_random = urandom(200000)
Timer(partial(bxor_add, first_random, second_random)).timeit(1)
#>>> 1.3261873809969984
Timer(partial(bxor_inplace, first_random, second_random)).timeit(1)
#>>> 0.03055390200461261
Timer(partial(bxor_join, first_random, second_random)).timeit(1)
#>>> 0.15852201101370156
Timer(partial(bxor_append, first_random, second_random)).timeit(1)
#>>> 0.030534288001945242
first_random = urandom(10000000)
second_random = urandom(10000000)
Timer(partial(bxor_inplace, first_random, second_random)).timeit(1)
#>>> 1.5432947289955337
Timer(partial(bxor_join, first_random, second_random)).timeit(1)
#>>> 7.90503858300508
Timer(partial(bxor_append, first_random, second_random)).timeit(1)
#>>> 1.5145326450001448
I'd go with the append version for clarity and speed.
For clarification, I don't think the append method is meaningfully faster than the inplace version; I just think it's a tiny bit more straightforward.
Nevertheless, because it was requested:
first_random = urandom(100000)
second_random = urandom(100000)
min(Timer(partial(bxor_inplace, first_random, second_random)).repeat(10, 100))
#>>> 1.5381054869794752
min(Timer(partial(bxor_append, first_random, second_random)).repeat(10, 100))
#>>> 1.5196998479950707
