[R] Discretization of numeric attributes

[ripley@stats.ox.ac.uk]

On Tue, 7 May 2002, Hans W. Borchers wrote:

>
> >
> >rpart and tree, for example.
> Yes, I know that recursive partitioning does some kind of splitting
> numerical variables. I looked into 'rpart.chm', but could not identify a
> function that I could call. What I would need is something like
>
> discretize(num.var, some.factor, method="FayyadIrani, MDL, Kononenko, C45")
>
> giving back a factor variable with selected intervals or splitting points
> as names. Can I extract something similar from one of the packages rpart or
> tree?

Think about what the top level split in a tree does.  You could alos
extract the C routines used.

You are misusing the terms though: C4.5 is not a splitting rule but a
tree-construction and pruning algorithm, and MDL is a principle to choose
complexity.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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