Blog "about python 3"

[Mark Lawrence]

On 02/01/2014 17:36, Robin Becker wrote:
> On 31/12/2013 15:41, Roy Smith wrote:
>> I'm using 2.7 in production.  I realize that at some point we'll need to
>> upgrade to 3.x.  We'll keep putting that off as long as the "effort +
>> dependencies + risk" metric exceeds the "perceived added value" metric.
>>
> We too are using python 2.4 - 2.7 in production. Different clients
> migrate at different speeds.
>
>>
>> To be honest, the "perceived added value" in 3.x is pretty low for us.
>> What we're running now works.  Switching to 3.x isn't going to increase
>> our monthly average users, or our retention rate, or decrease our COGS,
>> or increase our revenue.  There's no killer features we need.  In
>> summary, the decision to migrate will be driven more by risk aversion,
>> when the risk of staying on an obsolete, unsupported platform, exceeds
>> the risk of moving to a new one.  Or, there will be some third-party
>> module that we must have which is no longer supported on 2.x.
>>
>
> +1
>
>> If I were starting a new project today, I would probably start it in 3.x.
> +1
>
> I just spent a large amount of effort porting reportlab to a version
> which works with both python2.7 and python3.3. I have a large number of
> functions etc which handle the conversions that differ between the two
> pythons.
>
> For fairly sensible reasons we changed the internal default to use
> unicode rather than bytes. After doing all that and making the tests
> compatible etc etc I have a version which runs in both and passes all
> its tests. However, for whatever reason the python 3.3 version runs slower
>
> 2.7 Ran 223 tests in 66.578s
>
> 3.3 Ran 223 tests in 75.703s
>
> I know some of these tests are fairly variable, but even for simple
> things like paragraph parsing 3.3 seems to be slower. Since both use
> unicode internally it can't be that can it, or is python 2.7's unicode
> faster?
>
> So far the superiority of 3.3 escapes me, but I'm tasked with enjoying
> this process so I'm sure there must be some new 'feature' that will
> help. Perhaps 'yield from' or 'raise from None' or .......
>
> In any case I think we will be maintaining python 2.x code for at least
> another 5 years; the version gap is then a real hindrance.

Of interest 
https://mail.python.org/pipermail/python-dev/2012-October/121919.html ?

-- 
My fellow Pythonistas, ask not what our language can do for you, ask 
what you can do for our language.

Mark Lawrence