On Fri, 7 Aug 2009 09:43:54 pm Tal Einat wrote:
You can already do bitwise operations on bytes,
Are you sure about that? I tried looking it up in the docs, but python.org is down at the moment, so excuse me if I've missed something obvious. In Python 3.0:
b'ABCD' & 255 Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: unsupported operand type(s) for &: 'bytes' and 'int'
b'ABCD' & b'\xff' Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: unsupported operand type(s) for &: 'bytes' and 'bytes'
Have I missed something?
As I see it, the major underlying problem here is that byte-arrays are immutable, since what you really want is to be able to change a single byte of the array in-place.
I'm not speaking for the original poster, but for myself, not necessarily. While it would be nice to be able to flip bits directly, I'd be happy with bitwise operators to return new instances, as they currently do for ints. Something like: # not actual code
bb = bytes("ABCD") bb &= b"\xff\0" bb b"C\0"
This could work for bit-flipping operations, although I'd welcome an easier to use API: # still not actual code
bb = bytes("ABCD") bb |= (2**5)*256 # set the 5th bit of the 2nd byte bb b"ABcD"
-- Steven D'Aprano