a = 'abcd'

a1 = bytes(a,encoding('utf-8'))

a = b'abcd'

a1 = bytes.decode(a , encoding('utf-8'))

a='01 02 03 04 05 06'

a1 = a.replace(' ' ,'')

a2 = bytes,fromhex(a1)

"".join(['%02X ' % b for b in bs])

b = b'\x12\x34'

n = int.from_bytes(b,byteorder='big',signed=False)

#b'\x12\x34'->4660

n = 4660

b = n.to_bytes(length=2,byteorder='big',signed=False)

#4660->b'\x12\x34'

bytearray()

bytearray(整数n)

bytearray(整型可迭代对象)
bytearray(b'字符串')
bytearray(字符串, encoding='utf-8')

>>> bytearray()

bytearray(b'')

>>> bytearray([1,2,3])

bytearray(b'\x01\x02\x03')

>>> bytearray(["a","b","c"])

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

TypeError: an integer is required

>>> bytearray(3)

bytearray(b'\x00\x00\x00')

>>> bytearray("abc",encoding="utf-8")

bytearray(b'abc')

>>> bytearray("abc")

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

TypeError: string argument without an encoding