New Python 3.0 string formatting - really necessary?

Steven D'Aprano steve at
Sun Dec 21 11:14:24 CET 2008

On Sun, 21 Dec 2008 00:57:46 -0800, Patrick Mullen wrote:

> 2) In my experience, major version changes tend to be slower than
> before.  When a lot of things change, especially if very low-level
> things change, as happened in python 3.0, the new code has not yet went
> through many years of revision and optimization that the old code has. 

I was around for the change from Python 1.5 -> 2.x. By memory, I skipped 
a couple of versions... I think I didn't make the move until Python 2.2 
or 2.3 was released. Python 2.0 was significantly slower than 1.5 in a 
number of critical areas, but not for long.

Actually, it's quite possible that Python 1.5 is still faster than Python 
2.x in some areas -- but of course it misses a lot of features, and at 
the end of the day, the difference between your script completing in 0.03 
seconds or in 0.06 seconds is meaningless.

> In my opinion, python 3 was rushed out the door a bit.  It could have
> done with a few more months of optimization and polishing. However, on
> the other hand, it is going to take so long for python infrastructure to
> convert to python 3, that an earlier release makes sense, even if it
> hasn't been excessively polished.  The biggest reason for the speed
> change is the rewritten stdio and unicode-everything.  Hopefully this
> stuff can be improved in future updates.  I don't think anyone WANTS
> cpython to be slower.

I understand that the 3.0.1 release due out around Christmas will have 
some major speed-ups in stdio.


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