Re: [R] Error: Can not handle categorical predictors with more than 32 categories.

From: Uwe Ligges <ligges_at_statistik.uni-dortmund.de>
Date: Wed 23 Mar 2005 - 18:32:25 EST

Melanie Vida wrote:

> Hi All,
>
> My question is in regards to an error generated when using randomForest
> in R. Is there a special way to format the data in order to avoid this
> error, or am I completely confused on what the error implies?
>
> "Error in randomForest.default(m, y, ...) :
> Can not handle categorical predictors with more than 32 categories."
>
> This is generated from the command line:
> > credit.rf <- randomForest(V16 ~ ., data=credit, mtry=2, importance =
> TRUE, do.trace=100)
>
> The data set is the credit-screening data from the UCI respository,
> ftp://ftp.ics.uci.edu/pub/machine-learning-databases/credit-screening/crx.data.
> This data consists of 690 samples and 16 attributes.
> The attribute information includes:
>
> A1: b, a.
> A2: continuous.
> A3: continuous.
> A4: u, y, l, t.
> A5: g, p, gg.
> A6: c, d, cc, i, j, k, m, r, q, w, x, e, aa, ff.
> A7: v, h, bb, j, n, z, dd, ff, o.
> A8: continuous.
> A9: t, f.
> A10: t, f.
> A11: continuous.
> A12: t, f.
> A13: g, p, s.
> A14: continuous.
> A15: continuous.
> A16: +,- (class attribute)
>
> Has anyone tried randomForests in R on the credit-screening data set
> from the UCI repository?

For sure you forgot to set na.strings = "?" in read.table().... Look at str(credit) to see that some numerics had been converted to factors for that reason.

Uwe Ligges

> Thanks in advance for any useful hints and tips,
>
> Melanie
>
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R-help@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 Received on Wed Mar 23 18:42:23 2005

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