[Python-Dev] Usage of += on strings in loops in stdlib (original) (raw)

Chris Withers chris at python.org
Wed Feb 13 10:09:34 CET 2013


On 12/02/2013 21:03, Maciej Fijalkowski wrote:

We recently encountered a performance issue in stdlib for pypy. It turned out that someone commited a performance "fix" that uses += for strings instead of "".join() that was there before.

That's... interesting.

I fixed a performance bug in httplib some years ago by doing the exact opposite; += -> ''.join(). In that case, it changed downloading a file from 20 minutes to 3 seconds. That was likely on Python 2.5.

How people feel about generally not having += on long strings in stdlib (since the refcount = 1 thing is a hack)?

+1 from me.

Chris

-- Simplistix - Content Management, Batch Processing & Python Consulting - http://www.simplistix.co.uk



More information about the Python-Dev mailing list