decision tree by python

[Tim Churches]

Laurence Gonsalves wrote:
> 
> On Wed, 6 Nov 2002 16:06:14 -0500,
> Chermside, Michael <mchermside at ingdirect.com> wrote:
> > > i am trying to construct a decision and classifiy a set
> > > of data using GINI index.
> > > Is there any references?
> >
> >  I'm really not quite sure what you're asking for. The phrase
> >  "construct a decision" suggests that you're trying to build
> >  some object... but I'm not sure what a "decision object" would
> >  be. Alternatively, you may simply not be a native English
> >  speaker and you simply meant you wanted to "make a decision".
> >  That's fine, but without SOME SORT of description of WHAT
> >  decision, it's hard to find a resource.
> 
> Or maybe they made typo. :-)
> 
> The subject says "decision tree", so I'm guessing they want to construct
> a decision tree for classifying data using the GINI index.
> 
> The ID3 decision tree learning algorithm is described on this page:
> 
>   http://www.cs.tufts.edu/g/150ML/slides/id3.html
> 
> Converting it to Python isn't too difficult.

Orange might be worth a look (see http://magix.fri.uni-lj.si/orange/ ) -
it implements some elementary classifiers as well as a wrapper for C4.5,
which is a further development of ID3 (and also freely available, unlike
the proprietary C5.0 algorithm).

Peter Christen at ANU has also written a very nice Pythonic C-level
interface to the C4.5 code, but I'm not sure whether he has released it
- see http://cap.anu.edu.au/cap/projects/KDDMemPerf/ for more details.

Tim C