bytearray

Types str and bytes are immutable. As we learned in previous posts, + is optimized for str but sometimes you need a fairly mutable type. For such cases, there is bytearray type. It is a "hybrid" of bytes and list:

b = bytearray(b'hello, ')
b.extend(b'@pythonetc')
b
# bytearray(b'hello, @pythonetc')

b.upper()
# bytearray(b'HELLO, @PYTHONETC')

The type bytearray has all methods of both bytes and list except sort:

set(dir(bytearray)) ^ (set(dir(bytes)) | set(dir(list)))
# {'__alloc__', '__class_getitem__', '__getnewargs__', '__reversed__', 'sort'}

If you're looking for reasons why there is no bytearray.sort, there is the only answer we found: stackoverflow.com/a/22783330/8704691.