Re: [R] Classification tree data structure

From: Prof Brian Ripley <>
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,        
Professor of Applied Statistics,
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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