python bijection

[Lie Ryan]

On 12/5/2009 9:41 AM, Carl Banks wrote:
> On Dec 4, 12:46 pm, geremy condra<debat... at gmail.com>  wrote:
> more common than full-blown graph package).
>> Sure, its a tree, which is also a graph. In this case it looks to
>> me more like a directed acyclic graph than anything, but its
>> pretty much just semantics since the interface is functionally
>> equivalent.
>
> I'd have to agree with Lie, yes a tree is a graph, but it's simply not
> an argument that Python community is grasping for graph structures.
> It's like arguing that the Python community could benefit from a
> quaternion type, because quaternions are actually heavily used in
> Python, because a scalar number is a quarternion.
 >
> Carl Banks
>
> (Would be +1 on a good graph implementation... just not because of
> ElementTree.)

I think this could be an interpretation of the Zen:

Simple is better than complex.
Complex is better than complicated.

can be read as:
List is better than Tree
Tree is better than Graph

not having Tree and Graph package in the standard library force most 
people to find List-based solution. And people that know they need 
graphs will find them in 3rd party modules. I have needed Trees a few 
times in python, but very rarely a Graph (except for playing around). 
YMDWV (your mileage definitely will vary).