Feasible in Python ? list of object , with two exeptional objects

[Osiris]

On Wed, 27 Dec 2006 23:27:08 +0100, Marc 'BlackJack' Rintsch
<bj_666 at gmx.net> wrote:

>In <6eo5p2di7lrcs5smouhg8ju83901b4hld0 at 4ax.com>, Osiris wrote:
>
>> I have an array (I come from C) of identical objects, called sections.
>> These sections have some feature, say a length, measured in mm, which
>> is calculated by a method A_length of the instantiation of the
>> Section's class.
>> Only, two elements in the array (or list ?) have a length that must be
>> calculated according to a totally different procedure, a different
>> function or method.
>
>Is this something that the instances of section "know" or is some external
>"knowledge" needed to identify those special objects?

the sections know, beforehand. I can write the method NOW.
>
>> After calculation of ALL the lengths, they must be added together and
>> output.
>> The calculation procedure screams for a FOR or a WHILE loop allong the
>> list of sections, only those two sections mentioned make life
>> difficult.
>
>Sounds like something like ``sum(section.length() for section in sections)``.
>
>Your description is a bit vague.  Where and how do you start to treat the
>objects different.

I create all sections, also the differeent one. I know all along which
is differeent.

>  Is it possible to decide at instantiation time to
>create a `Section` object or a `SpecialSection` object?  How much

YES

>different is the calculation?

rather al lot.

>  Do you need two separate classes or just
>one with a flag or maybe a function as argument to the `__init__()`

is differenter than that..

>method?  Are you writing the `Section` class(es) just for this
>calculation or do they contain other behavior too?
>

They have a lot of other behavior too...

>Ciao,
>	Marc 'BlackJack' Rintsch