[R] Usage of rJava (.jcall) with Weka functions, any example?

Josep Maria Campanera Alsina campaxic at gmail.com
Wed Jul 2 16:28:54 CEST 2008


Dear All,

I'd like to use Weka functions that are not implemented (do not have
interface) in RWeka, like the Remove function and others in the
future!

The .java() functionality is for that purpose but I haven't seen any
example with Weka functions. Could anyone give me hand in how to do
it? For instace if I want to use the
weka.filters.unsupervised.attribute.Remove?

1. in the R console, first I load a matrix file,

> matrix <- read.table(fileName, header=TRUE)

OK!
2. Second, I f I want to remove the first attribute with Weka:

> library(grid)
> library(rJava)
> library(RWeka)
> c <- .jcall("weka/filters/unsupervised/attribute/Remove","S","Remove","-R","1",matrix)

Is it that right?

I get this message error!

method Remove with signature
(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;
not found

I've played around but I cannot get through!

All help will be appreciated! Thank you very much!

Josep Maria,

----------------------------------------------------------------------------

>>>>>> Josep Maria Campanera Alsina writes:
>
>> Dear Kurt Hornik,
>> I'm interested in Rweka. I've downloaded the manual for version
>> 0.3-10. I'd like to know if all functionalities of Weka 3.5.7 are
>> integrated in Rweka. For instance I cannot see any reference to the
>> Database loader in the Rweka manual although it is a functionality of
>> weka.
>
> RWeka comes with all of Weka, but not all of Weka has high-level R
> interfaces.  You can still use these parts using the low-level .jcall()
> mechanisms provided by the rJava layer.
>
> Best
> -k
>
>> Thanks a lot,
>
>> Josep Maria,



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