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

[Marc 'BlackJack' Rintsch]

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?

> 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.  Is it possible to decide at instantiation time to
create a `Section` object or a `SpecialSection` object?  How much
different is the calculation?  Do you need two separate classes or just
one with a flag or maybe a function as argument to the `__init__()`
method?  Are you writing the `Section` class(es) just for this
calculation or do they contain other behavior too?

Ciao,
	Marc 'BlackJack' Rintsch