Byte Array to Hex String

Using str.format:

>>> array_alpha = [ 133, 53, 234, 241 ]>>> print ''.join('{:02x}'.format(x) for x in array_alpha)8535eaf1

or using format

>>> print ''.join(format(x, '02x') for x in array_alpha)8535eaf1

Note: In the format statements, the 02 means it will pad with up to 2 leading 0s if necessary. This is important since [0x1, 0x1, 0x1] i.e. (0x010101) would be formatted to "111" instead of "010101"

or using bytearray with binascii.hexlify:

>>> import binascii>>> binascii.hexlify(bytearray(array_alpha))'8535eaf1'

Here is a benchmark of above methods in Python 3.6.1:

from timeit import timeitimport binasciinumber = 10000def using_str_format() -> str:    return "".join("{:02x}".format(x) for x in test_obj)def using_format() -> str:    return "".join(format(x, "02x") for x in test_obj)def using_hexlify() -> str:    return binascii.hexlify(bytearray(test_obj)).decode('ascii')def do_test():    print("Testing with {}-byte {}:".format(len(test_obj), test_obj.__class__.__name__))    if using_str_format() != using_format() != using_hexlify():        raise RuntimeError("Results are not the same")    print("Using str.format       -> " + str(timeit(using_str_format, number=number)))    print("Using format           -> " + str(timeit(using_format, number=number)))    print("Using binascii.hexlify -> " + str(timeit(using_hexlify, number=number)))test_obj = bytes([i for i in range(255)])do_test()test_obj = bytearray([i for i in range(255)])do_test()

Result:

Testing with 255-byte bytes:Using str.format       -> 1.459474583090427Using format           -> 1.5809937679100738Using binascii.hexlify -> 0.014521426401399307Testing with 255-byte bytearray:Using str.format       -> 1.443447684109402Using format           -> 1.5608712609513171Using binascii.hexlify -> 0.014114164661833684

Methods using format do provide additional formatting options, as example separating numbers with spaces " ".join, commas ", ".join, upper-case printing "{:02X}".format(x)/format(x, "02X"), etc., but at a cost of great performance impact.

Consider the hex() method of the bytes type on Python 3.5 and up:

>>> array_alpha = [ 133, 53, 234, 241 ]>>> print(bytes(array_alpha).hex())8535eaf1

EDIT: it's also much faster than hexlify (modified @falsetru's benchmarks above)

from timeit import timeitN = 10000print("bytearray + hexlify ->", timeit(    'binascii.hexlify(data).decode("ascii")',    setup='import binascii; data = bytearray(range(255))',    number=N,))print("byte + hex          ->", timeit(    'data.hex()',    setup='data = bytes(range(255))',    number=N,))

Result:

bytearray + hexlify -> 0.011218150997592602byte + hex          -> 0.005952142993919551

hex_string = "".join("%02x" % b for b in array_alpha)