[Python-ideas] bytes indexing behavior

[Serhiy Storchaka]

On 07.06.16 07:48, Guido van Rossum wrote:
> On Monday, June 6, 2016, Serhiy Storchaka
> <storchaka at gmail.com
> <mailto:storchaka at gmail.com>> wrote:
>
>     On 06.06.16 23:28, Guido van Rossum wrote:
>
>         I think the approach using a new method for the old behavior is
>         workable. Maybe we should add another (temporary) new method for
>         the new
>         behavior.
>
>         The magic object approach is too magical.
>
>         We should do the same for bytearray and memoryview.
>
>
>     I often use bytearray and memoryview as arrays of ints.
>
>
> Really short ints. :-). But you should really use the array module instead.

Yes, ints of known width (even 1-bit ints in sre_compile.py). Using the 
array module requires additional copying. Aren't bytearray and 
memoryview here for avoiding unnecessary copying?

> Anyway we should do this for all three or for none.

I think representing bytes as an array of ints was good decision. If you 
need indexing to return a substring, you should use str instead. It is 
as well memory efficient thanks to PEP 393.