[Tutor] python varying mulitple inheritance

Alan Gauld alan.gauld at btinternet.com
Tue Jun 19 09:38:55 CEST 2012

On 19/06/12 06:14, kendy at kendy.org wrote:
> Hmmm. No need to write the whole thing written out. Just how not to code:
> class Pocket1(Wallet, Keys, Comb, Usb, CellPhone, WorkBadge):
> class Pocket2(Wallet, Keys, Comb, Usb, CellPhone):
> class Pocket3(Wallet, Keys, Comb, Usb,            WorkBadge):
> class Pocket4(Wallet, Keys, Comb, Usb):
> class Pocket5(Wallet, Keys, Comb,      CellPhone, WorkBadge):
> class Pocket6(Wallet, Keys, Comb,      CellPhone):
> ...

Back to basics. a class is a definition of a *type* of thing, not a 
particular case. A Pocket is a general purpose container. Each instance 
can hold many things. So you would normally expect one pocket class and 
6 instances. Each instance holding a different list of items.

The only time you need a different Pocket class is where the pocket has 
different *behaviour*. It is normally the behaviours that differentiate 
classes not the data. The class data is there to support the class 
behaviour. The behaviour of a Pocket is probably some thing like:

In most implementations a Pocket will look a lot like a list...

Alan G
Author of the Learn to Program web site

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