Python Gotcha's?

[Paul Rubin]

Steven D'Aprano <steve+comp.lang.python at pearwood.info> writes:
>> Running both Python 2 and Python 3 on Windows is painful where it
>> doesn't need to be.
> And how is that different from any other two versions of Python?

1. The backwards incompatibility between 2 and 3 is much more serious
than between 2.x and 2.(x-1).  

2. There is not much reason to run multiple 2.x's on the same system.

> Going from 2.5 to 2.6 can cause breakage; 

That should be considered a bug in 2.6, but in any case it doesn't come
into play that often.  It's nothing like the 3.x changes.

> on the other hand with care you can support 2.6-3.2. 

The idea of the incompatibilities introduced to 3.x is that people
should USE them, since they supposedly make the language better.
Therefore "with care" goes against their purpose.  Also, "with care"
only applies to script you write yourself.  If you download a script
from somewhere else that relies on 3.x, you have to modify it to work
under 2.x and vice versa.  If you download both kinds of scripts you
have to modify some of them or else run two Pythons.