Creating Classes

Dave Angel davea at ieee.org
Sat Dec 19 05:49:16 CET 2009



Alf P. Steinbach wrote:
> <div class="moz-text-flowed" style="font-family: -moz-fixed">* Dave 
> Angel -> seafoid:
>>
>> One other point:  you should always derive a class from some other 
>> class, or 'object' by default.  So you should being the class 
>> definition by:
>>
>> class Seq(object):
>>
>> Why?  It mainly has to do with super().  But in any case if you omit 
>> the 'object' it's an "old style" class, and that's not even supported 
>> in 3.x, so it's better to just get in the habit before it matters.
>
> I think it's best to mention that the above applies to Python 2.x.
>
> In Python 3.x, writing
>
>    class Seq:
>
> is equivalent to writing
>
>    class Seq( object ):
>
> <snip>
We were talking about 2.x   And I explicitly mentioned 3.x because if 
one develops code that depends on old-style classes, they'll be in 
trouble with 3.x, which has no way to specify old-style classes.  In 
3.x, all classes are new-style.  And although it'll no longer matter 
whether you specify (object), it doesn't do any harm.  As I said, it's a 
good habit for a beginner to get into when defining classes.

DaveA




More information about the Python-list mailing list