[Python-Dev] Optimization

Antoine Pitrou solipsis at pitrou.net
Sun Oct 6 01:37:56 CEST 2013


On Sun, 6 Oct 2013 09:32:30 +1000
Nick Coghlan <ncoghlan at gmail.com> wrote:
> On 6 Oct 2013 08:59, "Antoine Pitrou" <solipsis at pitrou.net> wrote:
> >
> > On Sat, 5 Oct 2013 15:35:30 -0700
> > Raymond Hettinger <raymond.hettinger at gmail.com> wrote:
> > >
> > > Making bytearray's efficiently pop from the left side is dubious.
> > > This isn't a common idiom, nor should it be.  Even if all the
> > > other implementations could model this behavior, it wouldn't
> > > be a good idea to have bytearrays have different performance
> > > characteristics than strings.
> >
> > Bytearrays are mutable and strings are immutable, so evidently they
> > will have different performance characteristics.
> 
> I suspect "list" may have been the intended comparison there. "array.array"
> is another appropriate comparison.
> 
> Having bytearray operations differ in algorithmic complexity from those two
> types would be very strange and surprising (particularly if it was CPython
> specific).

It's only strange because you don't understand the main use case for
bytearrays. They may look like arrays of 8-bit integers but they are
really used for buffers, so optimizing for stuff like FIFO operation
makes sense.

Regards

Antoine.


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