[Tutor] Should I subclass UserDict or dict?

[Magnus Lyckå]

At 19:13 2003-05-09 -0700, Terry Carroll wrote:
>Should I inherit from the
>built-in dict class or from UserDict?

Use dict if you don't need to support Python versions < 2.2, and don't
plan to make the classes persistent with the ZOPE Object DataBase.

>On the only platform I plan to run this on, I run Python 2.2.2.  I know
>that dict is only inheritable from starting in 2.2.  Is 2.2 pervasive now

Yes, I think so.

>(my ISP's highest level of Python is 2.1.1, for example), or should I use

My ISP upgraded to 2.2 when I asked them. Have you asked?
(Don't forget to say please. :)

>UserDict to ensure compatibility?  Is there really any big advantage of
>user the built-in dict instead of UserDict?

Performance should be better I assume, but please measure. I assume
the two classes will be very similar, so I guess you can test both
ways.

I can't see that this is a big decision though. Surely it's easy
to rewrite as inheriting UserDict if there turns out to be problems
using dict as a base class. This is after all Python. One of the
big advantages with Python is that you can test different versions
easily.


--
Magnus Lycka (It's really Lyck&aring;), magnus@thinkware.se
Thinkware AB, Sweden, www.thinkware.se
I code Python ~ The shortest path from thought to working program