Python object overhead?

[Jean-Paul Calderone]

On Mon, 26 Mar 2007 09:13:58 -0600, Matt Garman <matthew.garman at gmail.com> wrote:
>On 3/23/07, Jack Diederich <jackdied at jackdied.com> wrote:
>> If you make the record a new style class (inherit from object) you can
>> specify the __slots__ attribute on the class.  This eliminates the per
>> instance dictionary overhead in exchange for less flexibility.
>
>When you say "new style class", do you mean that the __slots__ feature
>is only available in a newer version of Python?  Unfortunately, I'm
>stuck on 2.3.4 for this project.

A new-style class is one which has a type of type instead of ClassType.
For example:

  >>> class notnewstyle:
  ...     pass
  ...
  >>> type(notnewstyle)
  <type 'classobj'>
  >>> class newstyle(object):
  ...     pass
  ...
  >>> type(newstyle)
  <type 'type'>
  >>> class alsonewstyle(list):
  ...     pass
  ...
  >>> type(alsonewstyle)
  <type 'type'>
  >>>

2.3 has new-style classes.

Jean-Paul