Re: [R] Function to convert categorical variable in numerical

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Thu, 24 May 2007 10:36:04 +0100 (BST)

?model.matrix
?contr.treatment

Whether this makes sense for PCA is another matter: princomp() contains a test to stop this happening automatically with a formula argument. One problem is the result depends on just how you do the transformation.

On Thu, 24 May 2007, J.Andrés Martínez wrote:

> Hello everybody,
>
> I am a new R user. At current moment I need to do a Principal Components
> Analysis with a table who contain mixed variables (categorical and
> numerical). There is some function available in R for transform these
> variables?
>
> For example: I need transform the categorical variable X who has 3 classes
> in 2 numerical variables with 0s and 1s.
>
> Thank you very much,
> J. Andres
>
> [[alternative HTML version deleted]]
>
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>

-- 
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 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595


______________________________________________ R-help_at_stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.

Received on Thu 24 May 2007 - 09:43:40 GMT

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