[Python-Dev] PEP 467: Minor API improvements to bytes, bytearray, and memoryview (original) (raw)

Serhiy Storchaka storchaka at gmail.com
Wed Jun 8 04:53:06 EDT 2016

On 08.06.16 11:04, Victor Stinner wrote:

Currently, the bytes and bytearray constructors accept an integer argument and interpret it as meaning to create a zero-initialised sequence of the given size:: (...) This PEP proposes to deprecate that behaviour in Python 3.6, and remove it entirely in Python 3.7. I'm opposed to this change (presented like that). Please stop breaking the backward compatibility in minor versions.

The argument for deprecating bytes(n) is that this has different meaning in Python 2, and when backport a code to Python 2 or write 2+3 compatible code there is a risk to make a mistake. This argument is not applicable to bytearray(n).

If you still want to deprecate bytes(n), you must introduce an helper working on all Python versions. Obviously, the helper must be avaialble and work for Python 2.7. Maybe it can be the six module. Maybe something else.

The obvious way to create the bytes object of length n is b'\0' * n. It works in all Python versions starting from 2.6. I don't see the need in bytes(n) and bytes.zeros(n). There are no special methods for creating a list or a string of size n.

More information about the Python-Dev mailing list