[R] libary(Rweka) J48 design tree

[Achim Zeileis]

On Sun, 13 Nov 2011, RMSOPS wrote:

> Hello everybody
>
> I'm having some difficulties to design the decision tree algorithm J48.
> I am using the following code and when I run it gives me the following
> message
> plot(m1)
> Error in plot.Weka_tree(m1) :
>  Plotting of trees with multi-way splits is currently not implemented.

The package "partykit" which recently was released to CRAN should be able 
to help here:

library("partykit")
plot(as.party(m1))

Furthermore, write_to_dot(m1, "m1.dot") can always be used as described in

   Kurt Hornik, Christian Buchta, Achim Zeileis (2009) Open-Source
   Machine Learning: R Meets Weka. Computational Statistics, 24(2),
   225-232. doi:10.1007/s00180-008-0119-7

Either use Graphviz directoy on the .dot file or employ Rgraphviz which is 
hosted at Bioconductor:

   http://www.Bioconductor.org/packages/release/bioc/html/Rgraphviz.html

>
> #The code
> library(RWeka)
> library(randomForest)
> library(party)
> if(require(mlbench, quietly = TRUE) && require(party, quietly = TRUE))
> m1 <- J48(income2 ~ age+workclass+native.country, data = dataset)
> m1
> plot(m1)
> and results
> #M1 Results
> workclass = ?: <=50K (1433.0/120.0)
> workclass = Federal-gov: <=50K (696.0/281.0)
> workclass = Local-gov: <=50K (1542.0/469.0)
> workclass = Never-worked: <=50K (5.0)
> workclass = Private: <=50K (16939.0/3705.0)
> workclass = Self-emp-inc
> |   age <= 36: <=50K (205.0/65.0)
> |   age > 36: >50K (652.0/247.0)
> workclass = Self-emp-not-inc: <=50K (1926.0/525.0)
> workclass = State-gov: <=50K (1010.0/262.0)
> workclass = Without-pay: <=50K (13.0/2.0)
>
> Number of Leaves  : 	10
>
> Size of the tree : 	12
>
> I tried installing the package RGraphviz, but is not available in CRAN
> repository.
> I wonder if there is a package that lets you draw decision trees in a way
> more effective than the library(party)
>
> which the classification algorithms more efficient in R
>
> Thanks
>
> --
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