Home Original page

[Python-Dev] Usage of += on strings in loops in stdlib

Nick Coghlan ncoghlan at gmail.com
Wed Feb 13 08:52:56 CET 2013 
On Wed, Feb 13, 2013 at 5:42 PM, Alexandre Vassalotti
<alexandre at peadrop.com> wrote:
> On Tue, Feb 12, 2013 at 5:25 PM, Christian Tismer <tismer at stackless.com>
> wrote:
>>
>> Would ropes be an answer (and a simple way to cope with string mutation
>> patterns) as an alternative implementation, and therefore still justify
>> the usage of that pattern?
>
>
> I don't think so. Ropes are really useful when you work with gigabytes of
> data, but unfortunately they don't make good general-purpose strings.
> Monolithic arrays are much more efficient and simple for the typical
> use-cases we have in Python.

If I recall correctly, io.StringIO and io.BytesIO have been updated to
use ropes internally in 3.3. Writing to one of those and then calling
getvalue() at the end is the main alternative to the list+join trick
(when concatenating many small strings, the memory saving relative to
a list can be notable since strings have a fairly large per-instance
overhead).

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
More information about the Python-Dev mailing list