Performance problem with filtering

[Gustavo Cordova]

> 
> Anybody wrote a subclassed list yet that is optimized for 
> __contains__? Btw.
> this is different from a dictionary, as a list can contain 
> the same value twice.
> 
> Gerhard 
> -- 

The main hurdle is that the list is a general-purpose list,
and that means that you can't make any assumptions about
the data.

To make a fast list --for searches--, either:

1. Keep it sorted, and do a binary search when you need
   to find an element.

2. Keep it in a tree, and do a tree search when looking
   for an element.

Duplicated elements impact on the performance of this.

-gustavo