Re: [R] Classification tree data structure

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Wed 19 Oct 2005 - 02:18:39 EST

On Tue, 18 Oct 2005, Hades wrote:

> Hi there,
>
> I am growing classification trees using the 'tree' package add-on to R.
>
> I would like to convert the 'R' output to the SAS format used by Salford Systems' commercial CART software in order to interface with some
> other software.
>
> My question is:

> How can I parse the R tree data structure in order to infer the tree
> structure? The 'tree' class has a member '$frame' which gives the
> splits at each node, but as far as I can see does not specify the
> daughter nodes. Is this information accessible through the interface to
> class 'tree' or do I need to dive into the C code?

The daughter nodes of n are 2n and 2n+1. The print method, print.tree, is written entirely in R and shows you how to parse the tree (and you can see the pattern of the numbers from its result).

-- 
Brian D. Ripley,                  ripley@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 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Received on Wed Oct 19 02:35:35 2005

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